OUR COMMON INSECTS. 

 [Illustration: AMERICAN SILK WORM (MALE). ]

 OUR

 COMMON INSECTS. 

 A POPULAR ACCOUNT OF THE INSECTS

 OF OUR

 Fields, Forests, Gardens and Houses. 

 Illustrated with 4 Plates and 268 Woodcuts. 

 BY

 A. S. PACKARD, JR. , Author of "A GUIDE TO THE STUDY OF INSECTS. "

 SALEM. NATURALISTS' AGENCY. BOSTON: Estes & Lauriat. NEW YORK: Dodd & Mead. 1873. 

 Entered, according to Act of Congress, in the year 1878, by F. W. PUTNAM & CO. , in the Office of the Librarian of Congress at Washington. 

 PRINTED AT THE SALEM PRESS, F. W. PUTNAM & CO. , Proprietors. 

DEDICATION. 

TO SAMUEL H. SCUDDER. 

MY DEAR SCUDDER:--You and I were drawn together many years ago by acommon love for insects and their ways. 

I dedicate this little volume of ephemeral essays to you in recognitionof your worth as a man and a scientist, and as a token of warmfriendship. 

 Yours sincerely, A. S. PACKARD, JR. 

PREFACE. 

This little volume mainly consists of a reprint of a series of essayswhich appeared in the "American Naturalist" (Vols. I-v, 1867-71). It ishoped that their perusal may lead to a better acquaintance with thehabits and forms of our more common insects. The introduction waswritten expressly for this book, as well as Chapter XIII, "Hints on theAncestry of Insects. " The scientific reader may be drawn with greaterinterest to this chapter than to any other portion of the book. In thisdiscussion of a perhaps abstruse and difficult theme, his indulgence issought for whatever imperfections or deficiencies may appear. Oursystems of classification may at least be tested by the application ofthe theory of evolution. The natural system, if we mistake not, is thegenealogy of organized forms; when we can trace the latter, we establishthe former. Considering how much naturalists differ in their views as towhat is a natural classification, it is not strange that a genealogy ofanimals or plants seems absurd to many. To another generation ofnaturalists it must, perhaps, be left to decide whether to attempt theone is more unphilosophical than to attempt the other. 

Most of the cuts have already appeared in the "Guide to the Study ofInsects" and the "American Naturalist, " where their original sources aregiven, while a few have been kindly contributed by Prof. A. E. Verrill, the Boston Society of Natural History, and Prof. C. V. Riley, and threeare original. 

SALEM, June, 1873. 

OUR COMMON INSECTS. 

INTRODUCTORY. 

_What is an Insect?_ When we remember that the insects alone comprisefour-fifths of the animal kingdom, and that there are upwards of 200, 000living species, it would seem a hopeless task to define what an insectis. But a common plan pervades the structure of them all. The bodies ofall insects consist of a succession of rings, or segments, more or lesshardened by the deposition of a chemical substance called chitine; theserings are arranged in three groups: the head, the thorax, or middlebody, and the abdomen or hind body. In the six-footed insects, such asthe bee, moth, beetle or dragon fly, four of these rings unite early inembryonic life to form the head; the thorax consists of three, as may bereadily seen on slight examination, and the abdomen is composed eitherof ten or eleven rings. The body, then, seems divided or _insected_ intothree regions, whence the name _insect_. 

The head is furnished with a pair of antennæ, a pair of jaws(mandibles), and two pairs of maxillæ, the second and basal pair beingunited at their base to form the so-called labium, or under lip. Thesefour pairs of appendages represent the four rings of the head, to whichthey are appended in the order stated above. 

A pair of legs is appended to each of the three rings of the thorax;while the first and second rings each usually carry a pair of wings. 

The abdomen contains the ovipositor; sometimes, as in the bees andwasps, forming a sting. In the spiders (Fig. 1), however, there are noantennæ, and the second maxillæ, or labium, is wanting. Moreover, thereare four pairs of legs. The centipedes (Fig. 2, a Myriopod) also differfrom the rest of the insects in having an indefinite number of abdominalrings, each bearing a pair of legs. 

[Illustration: 1. Spider (Tegenaria). ]

On examining the arrangement of the parts within, we find the nervouscord, consisting of two chains of swellings, or nerve-knots, restingupon the floor or under side of the body; and the heart, or dorsalvessel, situated just under the skin of the back; and in looking atliving caterpillars, such as the cut-worm, and many thin-skinned aquaticlarvæ, we can see this long tubular heart pulsating about as often asour own heart, and when the insect is held against its will, or isagitated, the rapidity of the pulsations increases just as with us. 

[Illustration: 2. Centipede. ]

Insects do not breathe as in the higher animals by taking the air intothe mouth and filling the lungs, but there are a series of holes orpores along the side of the body, as seen in the grub of the humble bee, through which the air enters and is conveyed to every part of the bodyby an immense number of air tubes. (Fig. 3, air tubes, or tracheæ, inthe caudal appendage of the larva of a dragon fly). These air tubes areeverywhere bathed by the blood, by which the latter becomes oxygenated. 

[Illustration: 3. Caudal appendage of larva of Agrion. ]

Indeed the structure of an insect is entirely different from that of manor the quadrupeds, or any other vertebrate animal, and what we callhead, thorax, abdomen, gills, stomach, skin, or lungs, or jaws, arecalled so simply for convenience, and not that they are made in the sameway as those parts in the higher animals. 

An insect differs from a horse, for example, as much as a modernprinting press differs from the press Franklin used. Both machines aremade of iron, steel, wood, etc. , and both print; but the plan of theirstructure differs throughout, and some parts are wanting in the simplerpress which are present and absolutely essential in the other. So withthe two sorts of animals; they are built up originally out ofprotoplasm, or the original jelly-like germinal matter, which fills thecells composing their tissues, and nearly the same chemical elementsoccur in both, but the mode in which these are combined, the arrangementof their products: the muscular, nervous and skin tissues, differ in thetwo animals. The plan of structure, namely, the form and arrangement ofthe body walls, the situation of the appendages to the body, and of theanatomical systems within, i. E. , the nervous, digestive, circulatory, and respiratory systems, differ in their position in relation to thewalls of the body. Thus while the two sorts of animals reproduce theirkind, eat, drink and sleep, see, hear and smell, they perform these actsby different kinds of organs, situated sometimes on the most oppositeparts of the body, so that there is no comparison save in the resultswhich they accomplish; they only agree in being animals, and in having acommon animal nature. 

[Illustration: 4. Different forms of jaws. ]

[Illustration: 5. Mouth parts of the Larva of a Beetle. ]

[Illustration: 6. Maxilla of a Beetle. ]

_How Insects Eat. _ The jaws of insects (Fig. 4) are horny processessituated on each side of the mouth. They are variously toothed, so as totear the food, and move horizontally instead of up and down as in thehorse. The act of taking the food, especially if the insect becarnivorous in its habits, is quite complex, as not only the true jaws, but the accessory jaws (maxillæ, Fig. 5, _a_, upper, b, under side ofthe head of a young beetle; _at_, antennæ, _md_, mandible, _mx_, maxillæ, _mx_[1], labium) and the feelers (palpi) attached to themaxillæ, and the under lip (labium) are of great service in enabling theinsect to detect its food both by the senses of touch and smell. Themaxillæ are in the fully grown beetle (Fig. 6) divided into three lobes, the outermost forming the palpus, and the two others forming sharpteeth, often provided with hairs and minute brushes for cleansing theadjoining parts; these strong curved teeth are used in seizing the foodand placing it between the grinders, where it is crushed, prepared fordigestion and swallowed. Fig. 7 represents the mouth parts of the humblebee. (_b_, upper lip; _d_, mandible; _e_, maxilla; _f_, maxillarypalpus; _g_, tongue; _ih_, labium and tabial palpi; _k_, eye. )

[Illustration: 7. Mouth parts of a Humble Bee. ]

The alimentary canal passes through the middle of the body, the stomachforming usually a simple enlargement. Just before the stomach in certaininsects, as the grasshopper, is a gizzard armed with rows of powerfulhorny teeth for finely crushing grass. 

Insects eat almost incredible quantities of food when young and growingrapidly. Mr. Trouvelot tells us in the "American Naturalist" that thefood taken by a single American Silk-worm in fifty-six days is equal toeighty-six thousand times its primitive weight! On the other hand, afterthe insect has finished its transformations, it either takes no food atall, as in the May fly, or merely sips the honey of flowers, as in thebutterfly, while the June beetle and many others like it eat the leavesof trees, and the tiger and ground beetles feed voraciously on otherinsects. 

_How Insects Walk. _ In man and his allies, the vertebrates, the processof walking is a most difficult and apparently dangerous feat. Todescribe the mechanics of walking, the wonderful adaptation of themuscles and bones for the performance of this most ordinary action oflife, would require a volume. The process is scarcely less complex ininsects. Lyonnet found 3, 993 muscles in a caterpillar, and while a largeproportion belong to the internal organs, over a thousand assist inlocomotion. Hence the muscular power of insects is enormous. A flea willleap two hundred times its own height, and certain large, solid beetleswill move enormous weights as compared to the bulk of their bodies. 

[Illustration: 8. Larva of a beetle (Photuris). ]

In walking, as seen in the accompanying figure (Fig. 8), three legs arethrown forward at a time, two on one side and one on the other. 

Flies and many other insects can walk upside down, or on glass, aseasily as on a level surface. A fly's foot, as in most other insects, consists of five joints (tarsal joints), to the last one of which isappended a pair of stout claws, beneath which is a flat, soft, fleshycushion or pad, split into two (sometimes three) flaps, beset on theunder surface with fine hairs. A part of these hairs are swollen at theend, which is covered with "an elastic membranous expansion, capable ofclose contact with a highly polished surface, from which a minutequantity of a clear, transparent fluid is emitted when the fly isactively moving. " (T. West. ) These hairs are hence called holding, ortenent, hairs. With the aid of these, but mainly, as Mr. West insists, by the pressure of the atmosphere, a fly is enabled to adhere toperfectly smooth surfaces. His studies show the following curious facts. "That atmospheric pressure, if the area of the flaps be aloneconsidered, is equal to just one-half the weight of a fly. If the areacovered by the tenent hairs be added, an increase of pressure is gained, equal to about one-fourth the weight of a fly. This leaves one-fourth tobe accounted for by slight viscidity of the fluid, by the action I haveso often alluded to, which may be called 'grasping, ' by molecularattraction, and, doubtless, by other agents still more subtle, withwhich we have at present scarcely any acquaintance. "

_How Insects Fly. _ Who of us, as remarked by an eminent ornithologist, can even now explain the long sustained, peculiar flight of the hawk, orturkey buzzard, as it sails in the air without changing the position ofits wings? and, we would add, the somewhat similar flight of abutterfly? It is the poetry of motion, and a marvellous exhibition ofgrace and ease, combined with a wonderful underlying strength andlightness of the parts concerned in flight. 

Before we give a partial account of the results obtained by the delicateexperiments of Professor Marey on the flight of birds and insects, ourreaders should be reminded of the great differences between an insectand a bird, remembering that the former, is, in brief, a chitinous sac, so to speak, or rather a series of three such spherical or ellipticalsacs (the head, thorax and abdomen); the outer walls of the body forminga solid but light crust, to which are attached broad, membranous wings, the wing being a sort of membranous bag stretched over a framework ofhollow tubes (the tracheæ), so disposed as to give the greatestlightness and strength to the wing. The wings are moved by powerfulmuscles of flight, filling up the cavity of the thorax, just as themuscles are the largest about the thorax of a bird. Moreover in thebodies of insects that fly (such as the bee, cockchafer, and dragonfly), as distinguished from those that creep exclusively, the air tubes(tracheæ) which ramify into every part of the body, are dilated here andthere, especially in the base of the abdomen, into large sacs, which arefilled with air when the insect is about to take flight, so that thespecific gravity of the body is greatly diminished. Indeed, these airsacs, dilatable at will by the insect, may be compared to the swimmingbladder of fishes, which enables them to rise and fall at will todifferent levels in the sea, thus effecting an immense saving of thelabor of swimming. In the birds, as every body knows who has eaten achicken, or attended the dissection of a Thanksgiving turkey, the softparts are external, attached to the bony framework comprising theskeleton, the wing bones being directly connected with the central backbone; so that while these two sorts of animated flying machines are sodifferent in structure, they yet act in much the same manner when on thewing. The difference between them is clearly stated by Marey, some ofwhose conclusions we now give almost word for word. 

The flight of butterflies and moths differs from that of birds in thealmost vertical direction of the stroke of their wings, and in theirfaculty of sailing in the air without making any movements; thoughsometimes in the course they pursue they seem to resemble birds in theirflight. 

The flight of insects and birds moreover differs in the form of thetrajectory in space; in the inclination of the plane in which the wingsbeat; in the role of each of the two alternating (and in an inversesense) movements that the wings execute; as also in the facility withwhich the air is decomposed during these different movements. As thewings of a fly are adorned with a brilliant array of colors, we canfollow the trajectory or figure that each wing writes in the air. It isof the form of a figure of eight (Fig. 9), first discovered by ProfessorJ. Bell Pettigrew of Edinburgh. 

[Illustration: 9. Figure cut by an insect's wing. ]

[Illustration: 10. Figure cut by a bird's wing. ]

By an ingenious machine, specially devised for the purpose, ProfessorMarey found that a bird's wing moves in an ellipse, with a pointedsummit (Fig. 10). The insect beats the air in a distinctly horizontalplane, but the bird in a vertical plane. The wing of an insect isimpervious to the air; while the bird's wing resists the air only onits under side. Hence, there are two sorts of effects; in the insectthe up and down strokes are active; in the bird, the lowering of thewing is the only active period, though the return stroke seems tosustain the bird, the air acting on the wing. The bird's body ishorizontal when the wing gives a downward stroke; but when the beat isupward, the bird is placed in an inclined plane like a wingedprojectile, and mounts up on the air by means of the inclined surfacesthat it passively offers to the resistance of this fluid. 

[Illustration: 11. Trajectory of an insect's wing. ]

[Illustration: 12. Trajectory of a bird's wing. ]

In an insect, an energetic movement is equally necessary to strike theair at both beats up and down. In the bird, on the contrary, one activebeat only is necessary, the down beat. It creates at that time all themotive force that will be dispensed during the entire revolution of thewing. This difference is due to the difference in form of the wing. Thedifference between the two forms of flight is shown by an inspection ofthe two accompanying figures (11, 12). An insect's wing is small at thebase and broad at the end. This breadth would be useless near the body, because at this point the wing does not move swiftly enough to strikethe air effectively. The type of the insectean wing is designed, then, simply to strike the air. But in the bird the wing plays also a passiverole, _i. E. _, it receives the pressure of the air on its under sidewhen the bird is projected rapidly onward by its acquired swiftness. Inthese conditions the whole animal is carried onward in space; all thepoints of its wing have the same velocity. The neighboring regions ofthe body are useful to press upon the air, which acts as on a paperkite. The base of the wing also, in the bird, is broad, and providedwith feathers, which form a broad surface, on which the air presses witha force and method very efficacious in supporting the bird. Fig. 12gives an idea of this disposition of the wing at the active and passivetime in a bird. 

The inner half of the wing is the passive part of the organ, while theexternal half, that which strikes the air, is the active part. A fly'swing makes 330 revolutions in a second, executing consequently 660simple oscillations; it ought at each time to impress a lateraldeviation of the body of the insect, and destroy the velocity that thepreceding oscillation has given it in a contrary direction. So that bythis hypothesis the insect in its flight only utilizes fifty to onehundred parts (or one-half) of the resistance that the air furnishes it. 

[Illustration: 13. A bird on the wing. ]

In the bird (Fig. 13), at the time of lowering the wings, the obliqueplane which strikes the air, in decomposing the resistance, produces avertical component which resists the weight of the body, and ahorizontal component which imparts swiftness. The horizontal componentis not lost, but is utilized during the rise of the wing, as in a paperkite when held in the air against the wind. Thus the bird utilizesseventy-five out of one hundred parts of the resistance that the airfurnishes. The style of flight of birds is, therefore, theoreticallysuperior to that of insects. As to the division of the muscular forcebetween the resistance of the air and the mass of the body of the bird, we should compare the exertion made in walking on sand, for example, ascompared with walking on marble. This is easy to measure. When a fishstrikes the water with its tail to propel itself forward, it performs adouble task; one part consists in pushing backwards a certain mass ofwater with a certain swiftness, and the other in pushing on the body inspite of the resistance of the surrounding fluid. This last portion ofthe task only is utilized. It would be greater if the tail of the fishencountered a solid object. Almost all the propelling agencies employedin navigation undergo this loss of labor, which depends on the mobilityof the _point d' appui_. The bird is placed among conditions especiallyunfavorable. 

_The Senses of Insects. _ The eyes of insects are sometimes so large asto envelop the head like an Elizabethan ruffle, and the creature's head, as in the common house fly, seems all eyes. And this is almost literallythe case, as the two great staring eyes that almost meet on the top ofthe head to form one, are made up of myriads of simple eyes. Each facetor simple eye is provided with a nerve filament which branches off fromthe main optic nerve, so that but one impression of the object perceivedis conveyed to the brain; though it is taught by some that objectsappear not only double but a thousand times multiplied. But we shouldremember that with our two eyes we see double only when the brain isdiseased. Besides the large ordinary compound eyes, many insects possesssmall, simple eyes, like those of the spider. The great Germananatomist, Johannes Müller, believed that the compound eyes were adaptedfor the perception of distant objects, while those nearer are seen bythe simple eyes. But it may be objected to this view that the spiders, which have only simple eyes, apparently see both near and remote objectsas well as insects. 

The sense of touch is diffused all over the body. As in the hairs of thehead and face of man, those of insects are delicate tactile organs; andon the antennæ and legs (insects depending on this sense rather thanthat of sight) these appendages are covered with exquisitely finehairs. It is thought by some that the senses of hearing and smell arelodged in the antennæ, these organs thus combining the sense of feelingwith those of hearing and smelling. And the researches of anatomistslend much probability to the assertion, since little pits just under theskin are found, and even sometimes provided with grains of sand in theso-called ear of the lobster, etc. , corresponding to the ear bones ofthe higher animals, the pits being connected with nerves leading to thebrain. We have detected similar pits in the under side of the palpi ofthe Perla. It seems not improbable that these are organs of smell, andplaced in that part of the appendage nearest the mouth, so as to enablethe insect to select its proper food by its odor. Similar organs existon the caudal appendages of a kind of fly (Chrysopila), while the long, many-jointed caudal filaments of the cockroach are each provided withnearly a hundred of these little pits, which seem to be so many noses. Thus Lespès, a Swiss anatomist, in his remarks on the auditory sacs, which he says are found in the antennæ of nearly all insects, declaresthat as we have in insects compound eyes, so we have compound ears. Wemight add that in the abdominal appendage of the cockroach we have acompound nose, while in the feelers of the Perla, and the caudalappendage of the Chrysopila, the "nose" is simple. We might also referhere to Siebold's discovery of ears at the base of the abdomen of some, and in the forelegs of other kinds, of grasshoppers. Thus we need not besurprised at finding ears and noses scattered, as it were, sometimesalmost wantonly over the bodies of insects (in many worms the eyes arefound all over the body), while in man and his allies, from the monkeydown to the fish, the ears and nose invariably retain the same relativeplace in the head. 

_How Insects Grow. _ When beginning our entomological studies no factseemed more astonishing to our boyish mind than the thought that thelittle flies and midges were not the sons and daughters of the bigones. If every farmer and gardener knew this single fact it would beworth their while. The words _larva_ and _pupa_ will frequently occur insubsequent pages, and they should be explained. The caterpillar (Fig. 14, _a_) represents the earliest stage or babyhood of the butterfly, andit is called _larva_, from the Latin, meaning a mask, because it wasthought by the ancients to mask the form of the adult butterfly. 

[Illustration: 14. _a_ Larva, _b_ chrysalis of a butterfly. ]

When the caterpillar has ended its riotous life, for its appetite almosttransforms its being into the very incarnation of gluttony, it suddenly, as if repenting of its former life as a _bon vivant_, seeks a solitarycell or hole where like a hermit it sits and leads apparently about asuseless an existence. But meanwhile strange processes are going onbeneath the skin; and after a few convulsive struggles the back splitsopen, and out wriggles the chrysalis, a gorgeous, mummy-like form, itsbody adorned with golden and silvery spots. Hence the word chrysalis(Fig. 14, _b_), from the Greek, meaning golden, while the Latin word_pupa_, meaning a baby or doll, is indicative of its youth. In thisstate it hangs suspended to a twig or other object; while the silk worm, and others of its kind, previous to moulting, or casting their skins, spin a silken cocoon, which envelops and protects the chrysalis. 

[Illustration: 15. Imago or adult Butterfly. ]

At the given time, and after the body of the adult has fully formedbeneath the chrysalis skin, there is another moult, and the butterfly, with baggy, wet wings, creeps out. The body dries, the skin hardens, thewings expand, and in a few moments, sometimes an hour, the butterfly(Fig. 15) proudly sails aloft, the glory and pride of the insect world. 

We shall see in the ensuing chapters how varied are the larvæ and pupæof insects, and under what different guises insects live in their earlystages. 

[Illustration: Larva, pupa, and adult of a Leaf Beetle (Galeruca). ]

OUR COMMON INSECTS. 

CHAPTER I. 

THE HOME OF THE BEES. 

The history of the Honey bee, its wonderful instincts, its elaboratecells and complex economy, have engrossed the attention of the bestobservers, even from the time of Virgil, who sang of the Ligurian bee. The literature of the art of bee-keeping is already very extensive. Numerous bee journals and manuals of bee-keeping testify to theimportance of this art, while able mathematicians have studied the modeof formation of the hexagonal cells, [1] and physiologists haveinvestigated the intricate problems of the mode of generation anddevelopment of the bee itself. 

In discussing these difficult questions, we must rise from the study ofthe simple to the complex, remembering that--

 "All nature widens upward. Evermore The simpler essence lower lies: More complex is more perfect--owning more Discourse, more widely wise. "

and not forget to study the humbler allies of the Honey bee. We shall, in observing the habits and homes of the wild bees, gain a clearerinsight into the mysteries of the hive. 

The great family of bees is divided into social and solitary species. The social kinds live in nests composed of numerous cells in which theyoung brood are reared. These cells vary in form from those which arequite regularly hexagonal, like those of the Hive bee, to those whichare less regularly six-sided, as in the stingless bee of the tropics(Melipona), until in the Humble bee the cells are isolated andcylindrical in form. 

Before speaking of the wild bees, let us briefly review the life of theHoney bee. The queen bee having wintered over with many workers, laysher eggs in the spring, first in the worker, and, at a later period, inthe drone-cells. Early in the summer the workers construct the large, flask-shaped queen-cells, which are placed on the edge of the comb, andin these the queen larvæ are fed with rich and choice food. The oldqueen deserts the nest, forming a new colony. The new-born queen takesher marriage flight high in the air with a drone, and on her returnundertakes the management of the hive, and the duty of laying eggs. Whenthe supply of queens is exhausted, the workers destroy the drones. Thefirst brood of workers live about six weeks in summer, and then give wayto a new brood. The queens, according to Von Berlepsch, are known tolive five years, and during their whole life lay more than a millioneggs. 

In the tropics, the Honey bee is replaced by the Meliponas and Trigonas. They are minute, stingless bees, which store up honey and live incolonies often of immense extent. The cells of Melipona are hexagonal, nearly approaching in regularity those of the Hive bee, while the honeycells are irregular, being much larger cavities, which hold aboutone-half as much honey as a cell of the Humble bee. "Gardner, in histravels, states that many species of Melipona build in the hollow trunksof trees, others in banks; some suspend their nests from the branches oftrees, whilst one species constructs its nest of clay, it being of largesize. " (F. Smith. )

In a nest of the coal-black Trigona (Trigona carbonaria), from easternAustralia, Mr. F. Smith, of the British Museum, found from four hundredto five hundred dead workers, but no females. The combs were arrangedprecisely similar to those of the common wasp. The number of honey-potswhich were placed at the foot of the nest was two hundred and fifty. Mr. Smith inclines to the opinion that the hive of Trigona contains severalprolific females, as the great number of workers can only be thusexplained, and M. Guérin found six females in a nest of the Tawny-footedMelipona (M. Fulvipes). 

At home, our nearest ally of the true Honey bee, is the Humble bee(Bombus), of which over forty species are known to inhabit NorthAmerica. 

The economy of the Humble bee is thus: the queen awakens in early springfrom her winter's sleep under leaves or moss, or in the last year'snest, and selects a nesting place, generally in an abandoned nest of afield-mouse, or beneath a stump or sod, and "immediately, " according toMr. F. W. Putnam, [2] "collects" a small amount of pollen mixed withhoney, and in this deposits from seven to fourteen eggs, graduallyadding to the pollen mass until the first brood is hatched. She does notwait, however, for one brood to be hatched before laying the eggs ofanother, but, as soon as food enough has been collected, she lays theeggs for a second. The eggs are laid, in contact with each other, in onecavity of the mass of pollen, with a part of which they are slightlycovered. They are very soon developed; in fact, the lines are nowheredistinctly drawn between the egg and the larva, the larva and pupa, andagain between the latter and the imago; a perfect series, showing thisgradual transformation of the young to the imago can be found in almostevery nest. 

[Illustration: 15. Cell and Eggs of Bombus. ]

"As soon as the larvæ are capable of motion and commence feeding, theyeat the pollen by which they are surrounded, and, gradually separating, push their way in various directions. Eating as they move, andincreasing in size quite rapidly, they soon make large cavities in thepollen mass. When they have attained their full size, they spin a silkenwall about them, which is strengthened by the old bees covering it witha thin layer of wax, which soon becomes hard and tough, thus forming acell (Fig. 15, 1, cell containing a larva, on top of which (2) is apollen mass containing three eggs). The larvæ now gradually attain thepupa stage, and remain inactive until their full development. They thencut their way out, and are ready to assume their duties as workers, small females, males or queens. 

"It is apparent that the irregular disposition of the cells is due totheir being constructed so peculiarly by the larvæ. After the firstbrood, composed of workers, has come forth, the queen bee devotes hertime principally to her duties at home, the workers supplying the colonywith honey and pollen. As the queen continues prolific, more workers areadded, and the nest is rapidly enlarged. 

"About the middle of summer, eggs are deposited, which produce bothsmall females and males. " . .. "All eggs laid after the last of Julyproduce the large females, or queens, and, the males being still in thenest, it is presumed that the queens are impregnated at this time, as onthe approach of cold weather all except the queens, of which there areseveral in each nest, die. "

While the Humble bee in some respects shows much less instinct than thesolitary bees mentioned below, it stands higher in the series, however, from having workers, as well as males and females, who provide food forthe young. The labors of the Mason bees, and their allies, terminateafter the cell is once constructed and filled with pollen. The eggs arethen left to hatch, and the young care for themselves, though the adultbee shows greater skill in architecture than the Humble bee. It is thusthroughout nature. Many forms, comparatively low in the scale of life, astonish us with certain characters or traits, reminding us of beingsmuch superior, physically and intellectually. The lower forms constantlyreach up and in some way ally themselves with creatures far more highlyorganized. Thus the fish-like seal reminds us strikingly of the dog, both in the form of the head, in its docility and great intelligencewhen tamed, and even in its bark and the movements of the head. 

[Illustration: 16. Meloë. ]

The parasites of the Humble bee are numerous. Such are the species ofApathus, which so closely resembles the Humble bee itself, that itrequires long study to distinguish it readily. Its habits are not known, other than that it is found in the nests of its host. It differs fromthe Humble bee in having no pollen-basket, showing that its larvæ mustfeed on the food stored up by their host, as it does not itself collectit. The mandibles also are not, like those of Bombus, trowel-shaped forarchitectural purposes, but acutely triangular, and are probably notused in building. 

The caterpillars of various moths consume the honey and waxen cells; thetwo-winged flies, Volucella and Conops, and the larvæ of what is eitheran Anthomyia or Tachina-like fly, and several species of another genusof flies, Anthrax, together with several beetles, such as the Meloë(Fig. 16), Stylops (Fig. 17, male; 18_b_, female; _a_, position in thebody of its host), and Antherophagus prey upon them. 

[Illustration: 17. Male Stylops. ]

The power of boring the most symmetrical tunnels in solid wood reachesits perfection in the large Virginian Carpenter bee (Xylocopa Virginica, Fig. 19). This bee is as large as, and some allied exotic species areoften considerably larger than, the Humble bee, but not clothed withsuch dense hairs. We have received from Mr. James Angus, of West Farms, N. Y. , a piece of trellis from a grape vine, made of pine wood, containing the cells and young in various stages of growth, togetherwith the larvæ and chrysalids of Anthrax sinuosa (Fig. 20), a species offly parasitic on the larva. The maggot buries its head in the soft bodyof the young bee and feeds on its juices. 

Mr. Angus thus writes us regarding its habits, under date of July 19: "Iasked an intelligent and observing carpenter yesterday, if he knew howlong it took the Xylocopa to bore her tunnel. He said he thought shebored about one-quarter of an inch a day. I don't think myself shebores more than one-half inch, if she does that. If I mistake not, ittakes her about two days to make her own length at the first start; butthis being across the grain of the wood, may not be so easily done asthe remainder, which runs parallel with it. She always follows the grainof the wood, with the exception of the entrance, which is about her ownlength. The tunnels run from one to one and a half feet in length. Theygenerally run in opposite directions from the opening, and sometimesother galleries are run, one directly above the other, using the sameopening. I think they only make new tunnels when old ones are not to befound, and that the same tunnels are used for many years. Some of theold tunnels are very wide. I have found parts of them about an inch indiameter. I think this is caused by rasping off the sides to procure thenecessary material for constructing their cells. The partitions arecomposed of wood raspings, and some sticky fluid, probably saliva, tomake them adhere. 

[Illustration: 18. Female Stylops. ]

[Illustration: 19. Carpenter Bee. ]

"The tunnels are sometimes taken possession of by other bees and wasps. I think when this is the case, the Xylocopa prefers making a new cell, to cleaning out the dirt and rubbish of the other species. I frequentlyfind these bees remaining for a long time on the wing close to theopening, and bobbing their heads against the side, as if fanning airinto the opening. I have seen them thus employed for twenty minutes. Whether one bee or more makes the tunnel, that is, whether they taketurns in boring, I cannot at present say. In opening the cells (Fig. 21), more than one are generally found, even at this season. About twoweeks ago; I found as many as seven, I think, in one. "[3]

The hole is divided by partitions into cells about seven-tenths of aninch long. These partitions are constructed of the coarse dust orchippings made by the bee in eating out her cells, for our active littlecarpenter is provided with strong cutting jaws, moved by powerfulmuscles, and on her legs are stiff brushes of hair for cleaning out thetunnel as she descends into the heart of the solid wood. She must throwout the chips she bites off with her powerful mandibles from the sidesof the burrow, by means of her hind legs, passing the load of chipsbackwards out of the cell with her fore limbs, which she uses as hands. 

[Illustration: 20. Larva and Pupa of Anthrax. ]

The partitions are built most elaborately of a single flattened band ofchips, which is rolled up into a coil four layers deep. One side, forming the bottom of the cell, is concave, being beaten down andsmoothed off by the bee. The other side of the partition, forming thetop of the cell, is flat and rough. 

[Illustration: 21. Nest of Carpenter Bee. ]

At the time of opening the burrow, July 8th, the cells contained nearlyfull-grown larvæ, with some half developed. They were feeding on themasses of pollen, which were as large as a thick kidney bean, andoccupied nearly half the cell. The larvæ (Fig. 21) resemble those of theHumble bee, but are slenderer, tapering more rapidly towards each end ofthe body. 

The habits and structure of the little green Ceratina ally it closelywith Xylocopa. This pretty bee, named Ceratina dupla by Mr. Say, tunnelsout the stems of the elder or blackberry, syringa, or any pithy shrub, excavating them often to a depth of six or seven inches. She makes thewalls just wide enough to admit her body, and of a depth capable ofholding three or four, often five or six cells (Fig. 22). The finelybuilt cells, with their delicate silken walls, are cylindrical andnearly square at each end, though the free end of the last cell isrounded off. They are four and a half tenths of an inch long, and alittle over one-third as broad. The bee places them at nearly equaldistances apart, the slight interval between them being filled in withdirt. 

[Illustration: 22. Nest of Ceratina. ]

Dr. T. W. Harris states that May 15, 1832, one female laid its eggs inthe hollow of an aster stalk. Three perfect insects were disclosed fromit July 28th. The observations of Mr. Angus, who saw some bees makingtheir cells May 18th, also confirm this account. The history of ourlittle upholsterer is thus cleared up. Late in the spring she builds hercells, fills them with pollen, and lays one or more eggs upon each mass. Thus in about two months the insect completes its transformations;within this period passing through the egg, the larva and chrysalidstates, and then, as a bee, living a few days more, if a male; or if afemale, living through the winter. Her life thus spans one year. 

The larva (Fig. 23) is longer than that of Megachile, and compared withthat of Xylocopa, the different segments are much more convex, giving aserrate outline to the back of the worm. The pupa, or chrysalis, we havefound in the cells the last of July. It is white, and three-tenths of aninch long. It differs from that of the Leaf-cutter bee in having fourspines on the end of the body. 

[Illustration: 23. Larva of Ceratina. ]

[Illustration: 24. Nest of Tailor Bee. ]

In none of the wild bees are the cells constructed with more nicety thanthose of our little Ceratina. She bores out with her jaws a long deepwell just the size of her body, and then stretches a thin, delicatecloth of silk drawn tight as a drum-head across each end of herchambers, which she then fills with a mixture of pollen and honey. 

[Illustration: 25. Tailor Bee. ]

Her young are not, in this supposed retreat, entirely free from danger. The most invidious foes enter and attack the brood. Three species ofIchneumon flies, two of which belong to the Chalcid family, lay theireggs within the body of the larva, and emerge from the dried larva andpupa skins of the bee, often in great numbers. The smallest parasite, belonging to the genus Anthophorabia, so called from being first knownas a parasite on another bee (Anthophora), is a minute species foundalso abundantly in the tight cells of the Leaf-cutter bee. 

The interesting habits of the Leaf-cutting, or Tailor bee (Megachile), have always attracted attention. This bee is a stout, thick-bodiedinsect, with a large, square head, stout, sharp, scissors-like jaws, andwith a thick mass of stout, dense hairs on the under side of the tailfor carrying pollen, as she is not provided with the pollen-basket ofthe Honey and Humble bees. 

The Megachile lays its eggs in burrows in the stems of the elder (Fig. 24), which we have received from Mr. James Angus; we have also foundthem in the hollows of the locust tree. Mr. F. W. Putnam thus speaks ofthe economy of M. Centuncularis, our most common species. "My attentionwas first called, on the 26th of June, to a female busily engaged inbringing pieces of leaf to her cells, which she was building under aboard, on the roof of the piazza, directly under my window. Nearly thewhole morning was occupied by the bee in bringing pieces of leaf from arose bush growing about ten yards from her cells, returning at intervalsof a half minute to a minute with the pieces, which she carried in sucha manner as not to impede her steps when she alighted near her hole. "When the Leaf-cutter bee wishes to cut out a piece of a leaf (Fig. 25)she alights upon the leaf, and in a few seconds swiftly runs herscissors-like jaws around through it, bearing off the piece in her hindlegs. "About noon she had probably completed the cell, upon which shehad been engaged, as, during the afternoon, she was occupied in bringingpollen, preparatory to laying her single egg in the cell. For abouttwenty days the bee continued at work, building new cells and supplyingthem with pollen. .. . On the 28th of July, upon removing the board, itwas found that the bee had made thirty cells, arranged in nine rows ofunequal length, some being slightly curved to adapt them to the spaceunder the board. The longest row contained six cells, and was two and, three-quarters inches in length; the whole leaf structure being equal toa length of fifteen inches. Upon making an estimate of the pieces ofleaf in this structure, it was ascertained that there must have been atleast a thousand pieces used. In addition to the labor of making thecells, this bee, unassisted in all her duties, had to collect therequisite amount of pollen (and honey?) for each cell, and lay her eggstherein, when completed. Upon carefully cutting out a portion of one ofthe cells, a full-grown larva was seen engaged in spinning a slightsilken cocoon about the walls of its prison, which were quite hard andsmooth on the inside, probably owing to the movements of the larva, andthe consequent pressing of the sticky particles to the walls. In a shorttime the opening made was closed over by a very thin silken web. Thecells, measured on the inside of the hard walls, were . 35 of an inch inlength, and . 15 in diameter. The natural attitude of the larva issomewhat curved in its cell, but if straightened, it just equals theinside length of the cell. On the 31st of July, two female bees cameout, having cut their way through the sides of their cells. " In threeother cells "several hundred minute Ichneumons (Anthophorabiamegachilis) were seen, which came forth as soon as the cells wereopened. "

The habits of the little blue or green Mason bees (Osmia) are quitevaried. They construct their cells in the stems of plants, and in rottenposts and trees, or, like Andrena, they burrow in sunny banks. AEuropean species selects snail shells for its nest, wherein it buildsits earthen cells, while other species nidificate under stones. Curtisfound two hundred and thirty cocoons of a British species (Osmiaparetina), placed on the under side of a flat stone, of which one-thirdwere empty. Of the remainder, the most appeared between March and June, males appearing first; thirty-five more bees were developed thefollowing spring. Thus there were three successive broods, for threesucceeding years, so that these bees lived three years before arrivingat maturity. This may partly account for _insect years_, which are like"apple years, " seasons when bees and wasps, as well as other insects, abound in unusual numbers. 

[Illustration: 26. Nest of Osmia. ]

Mr. G. R. Waterhouse, in the Transactions of the Entomological Societyof London, for 1864, states that the cells of Osmia leucomelana "areformed of mud, and each cell is built separately. The female bee, having deposited a small pellet of mud in a sheltered spot between sometufts of grass, immediately begins to excavate a small cavity in itsupper surface, scraping the mud away from the centre towards the marginby means of her jaws. A small, shallow mud-cup is thus produced. It isrough and uneven on the outer surface, but beautifully smooth on theinner. On witnessing thus much of the work performed, I was struck withthree points: first, the rapidity with which the insect worked;secondly, the tenacity with which she kept her original position whilstexcavating; and thirdly, her constantly going over work which hadapparently been completed. .. . The lid is excavated and rendered concaveon its outer or upper surface, and is convex and rough on its innersurface; and, in fact, is a simple repetition of the first-formedportion of the cell, a part of a hollow sphere. "

The largest species of Osmia known to us is a very dark-blue species (O. Lignivora). We are indebted to a lady for specimens of the bees withtheir cells, which had been excavated in the interior of a maple treeseveral inches from the bark. The bee had industriously tunnelled outthis elaborate burrow (Fig. 26), and, in this respect, resembled thehabits of the Carpenter bee more closely than any other species of itsgenus. 

The tunnel was over three inches long, and about three-tenths of an inchwide. It contracted a little in width between the cell, showing that thebee worked intelligently, and wasted no more of her energies than wasabsolutely necessary. The burrow contained five cells, each half an inchlong, being rather short and broad, with the hinder end rounded, whilethe opposite end, next to the one adjoining, is cut off squarely. Thecell is somewhat jug-shaped, owing to a slight constriction just behindthe mouth. The material of which the cell is composed is stout, silken, parchment-like, and very smooth within. The interstices between thecells are filled in with rather coarse chippings made by the bee. 

The bee cut its way out of the cells in March, and lived for a monthafterwards on a diet of honey and water. It eagerly lapped up the dropsof water supplied by its keeper, to whom it soon grew accustomed, andseemed to recognize. 

Our smallest and most abundant species is the little green Osmiasimillima. It builds its little oval, somewhat urn-shaped cells againstthe roof of the large deserted galls of the oak-gall fly (Diplolepisconfluentus), placing them, in this instance eleven in number, in twoirregular rows, from which the mature bees issue through a hole in thegall (Fig. 27, with two separate cells). The earthen cells, containingthe tough dense cocoons, were arranged irregularly so as to fit theconcave vault of the larger gall, which was about two inches indiameter. On emerging from the cell the Osmia cuts out with its powerfuljaws an ovate lid, nearly as large as one side of the cell. 

[Illustration: 27. Nest of Osmia in a gall. ]

In the Harris collection are the cells and specimens of Osmia pacifica, the peaceful Osmia, which, according to the manuscript notes of Dr. Harris, is found in the perfect state in earthen cells beneath stones. The cell is oval cylindrical, a little contracted as usual with those ofall the species of the genus, thus forming an urn-shaped cell. It ishalf an inch long, and nearly three-tenths of an inch wide, while thecocoon, which is rather thin, is three-tenths of an inch long. We arenot acquainted with the habits of the larva and pupa in this country, but Mr. F. Smith states that the larva of the English species hatches ineight days after the eggs are laid, feeds ten to twelve days, when itbecomes full-grown, then spins a thin silken covering, and remains in aninactive state until the following spring, when it completes itstransformations. 

In the economy of our wild bees we see the manifestation of a wonderfulinstinct, as well as the exhibition of a _limited reason_. We canscarcely deny to animals a kind of reason which apparently differs _onlyin degree_ from that of man. Each species works in a sphere limited byphysical laws, but within that sphere it is a free agent. They haveenough of instinct and reason to direct their lives, and to enable themto act their part in carrying out the plan of creation. 

[Illustration: Paper Wasp. ]

FOOTNOTES:

[Footnote 1: The cells are not perfectly hexagonal. See the studies onthe formation of the cells of the bee, by Professor J. Wyman, in theProceedings of the American Academy of Arts and Sciences, Boston, 1866;and the author's Guide to the Study of Insects, p 123. ]

[Footnote 2: Notes on the Habits of the Humble Bee (Proceedings of theEssex Institute, vol. Iv, 1864, p. 101). 

Mr. Angus also writes us as follows concerning the habits of theWandering Humble bee (Bombus vagans): "I have found the males plentifulnear our garden fence, within a hole such as would be made by a mouse. They seem to be quite numerous. I was attracted to it by the noise theywere making in fanning at the opening. I counted at one time as many asseven thus employed, and the sound could be heard several yards off. Several males were at rest, but mostly on the wing, when they would makea dash among the fanners, and all would scatter and play about. Theworkers seem to be of a uniform size, and full as large as the males. Ithink the object of the fanning was to introduce air into the nest, asis done by the Honey bees. "]

[Footnote 3: "Since writing the above I have opened one of the new holesof Xylocopa, which was commenced between three and four weeks ago, in apine slat used in the staging of the greenhouse. The dimensions were asfollows:--Opening fully 3-8 wide; depth 7-16; whole length of tunnel 65-16 inches. The tunnel branched both ways from the hole. One end, fromopening, was 2 5-8, containing three cells, two with larva and pollen, the third empty. The other side of the opening, or the rest of thetunnel, was empty, with the exception of the old bee (only one) at work. I think this was the work of one bee, and, as near as I can judge, abouttwenty-five days' work. Width of tunnel inside at widest 9-16 inch. 

"I have just found a Xylocopa bobbing at one of the holes, and in orderto ascertain the depth of the tunnel, and to see whether there were anyothers in them, I sounded with a pliable rod, and found others in oneside, at a depth of five and one half inches; the other side was fourinches deep without bees. The morning was cool, so that the object inbobbing could not have been to introduce fresh currents of air, but musthave had some relation to those inside. Their legs on such occasionsare, as I have noticed, loaded with pollen. "]

CHAPTER II. 

THE HOME OF THE BEES. 

[_Concluded. _]

While the Andrena and Halictus bees, whose habits we now describe, areclosely allied in form to the Hive bee, socially they are the"mud-sills" of bee society, ranking among the lowest forms of the familyof bees. Their burrowing habits ally them with the ants, from whosenests their own burrows can scarcely be distinguished. Their economydoes not seem to demand the exercise of so much of a true reasoningpower and pliable instinct as characterizes bees, such as the Honey andHumble bee, which possess a high architectural skill. Moreover they arenot social; they have no part in rearing and caring for their young, afact that lends so much interest to the history of the Hive and Humblebee. In this respect they are far below the wasps, a family belongingnext below in the system of Nature. 

A glance at the drawing (Fig. 28), of a burrow, with its side galleries, of the Andrena vicina, reveals the economy of one of our most commonforms. Quite early in spring, when the sun and vernal breezes have driedup the soil, and the fields exchange their rusty hues for the rich greenverdure of May, our Andrena, tired of its idle life among the blossomsof the willow, the wild cherry, and garden flowers, suddenly becomesremarkably industrious, and wields its spade-like jaws and busy feetwith a strange and unwonted energy. Choosing some sunny, warm, grassybank (these nests were observed in the "great pasture" of Salem), notalways with a southern exposure however, the female sinks her deep wellthrough the sod from six inches to a foot into the sandy soil beneath. She goes to work literally tooth and nail. Reasoning from observationsmade on several species of wasps, and also from studying the structureof her jaws and legs, it is evident that she digs in and loosens thesoil with her powerful jaws, and then throws out the dirt with her legs. She uses her fore legs like hands, to pass the load of dirt to her hindlegs, and then runs backward out of her hole to dump it down behind her. Mr. Emerton tells me that he never saw a bee in the act of digging butonce, and then she left off after a few strokes. He also says, "they areharmless and inoffensive. On several occasions I have lain on the grassnear their holes for hours, but not one attempted to sting me; and whentaken between the fingers, they make but feeble resistance. "

[Illustration: Fig. 28. 

Nest (natural size) of Andrena vicina, showing the main burrow, and thecells leading from it; the oldest cell containing the pupa (_a_) issituated nearest the surface, while those containing the larva (_b_) liebetween the pupa and the cell (_e_) containing the pollen mass and eggresting upon it. The most recent cell (_f_) is the deepest down, andcontains a freshly deposited pollen mass. At _c_ is the beginning of acell; _g_, level of the ground. ]

To enter somewhat into detail, we gather from the observations of Mr. Emerton (who has carefully watched the habits of these bees throughseveral seasons) the following account of the economy of this bee: Onthe 4th of May the bees were seen digging their holes, most of whichwere already two inches deep, and one, six inches. The mounds of earthwere so small as to be hardly noticed. At this time an Oil beetle wasseen prowling about the holes. The presence of this dire foe of Andrenaat this time, it will be seen in a succeeding chapter on the enemies ofthe bees, is quite significant. By the 15th of May, hundreds of Andrenaholes were found in various parts of the pasture, and at one place, in aprevious season, there were about two hundred found placed within asmall area. One cell was dug up, but it contained no pollen. Four dayslater, several Andrenas were noticed resting from their toil at theopening of their burrows. On the 28th of May, in unearthing six holes, eight cells were found to contain pollen, and in two of them a smalllarva. The pellets of pollen are about the size of a small pea. They arehard and round at first, before the young has hatched, but as the larvagrows, the mass becomes softer and more pasty, so that the larva buriesits head in the mass, and greedily sucks it in. When is the pollengathered by the bee and kneaded into the pellet-like mass? On July 4th, a cell was opened in which was a bee busily engaged preparing thepollen, which was loosely and irregularly piled up, while there was alarva in an adjoining cell nearly half an inch long. It would seem, then, that the bee comes in from the fields laden with her stores ofpollen, which she elaborates into bee bread within her cell. 

When the bee returns to her cell she does not directly fly towards theentrance, since, as was noticed in a particular instance, she flew aboutfor a long time in all directions without any apparent aim, until shefinally settled near the hole, and walked into her subterranean retreat. On a rainy day, May 24th, our friend visited the colony, but found nobees flying about the holes. The little hillocks had been beaten down bythe pitiless raindrops, and all traces of their industry effaced. Ondigging down, several bees were found, indicating that on rainy daysthey seek the shelter of their holes, and do not take refuge underleaves of the plants they frequent. 

On the 29th of June, six full-grown larvæ were exhumed, and one, abouthalf grown. On the 20th of July, the colony seemed well organized, as, on laying open a burrow at the depth of six inches, he began to findcells. The upper ones, to the number of a dozen, were deserted andfilled with earth and grass roots, and had evidently been built and usedduring the previous year. Below these were eight cells placed around themain vertical gallery, reaching down to the depth of thirteen inches, and all containing nearly full-grown larvæ of the bees, or else those ofsome parasitic bee (Nomada) which had devoured the food prepared for theyoung Andrena. 

About the first of August the larva transforms to a pupa or chrysalis, as at this time two pupæ were found in cells a foot beneath the surface. As shown in the cut, those cells situated lowest down seem to be thelast to have been made, while the eggs laid in the highest are the firstto hatch, and the larvæ disclosed from them, the first to change topupæ. Four days later the pupæ of Cuckoo bees (Nomada) were found in thecells. No Andrenas were seen flying about at this time. 

On the 24th of August, to be still very circumstantial in our narrativethough at the risk of being tedious, three burrows were unearthed, andin them three fully formed bees were found nearly ready to leave theircells, and in addition several pupæ. In some other cells there werethree of the parasitic Nomada also nearly ready to come out, whichseemed to be identical with some bees noticed playing very innocentlyabout the holes early in the summer. 

On the last day of August, very few of the holes were open. A number ofOil beetles were strolling suspiciously about in the neighborhood, andsome little black Ichneumon flies were seen running about among theholes. 

During mid-summer the holes were found closed night and day by clods ofearth. 

The burrow is sunken perpendicularly, with short passages leading to thecells, which are slightly inclined downwards and outwards from the maingallery. The walls of the gallery are rough, but the cells are linedwith a mucous-like secretion, which, on hardening, looks like theglazing of earthenware. This glazing is quite hard, and breaks up intoangular pieces. It is evidently the work of the bee herself, and is notsecreted and laid on by the larva. The diameter of the interior of thecell is about one-quarter of an inch, contracting a little at the mouth. When the cell is taken out, the dirt adheres for a line in thickness, sothat it is of the size and form of an acorn. 

The larva of Andrena (Fig. 29) is soft and fleshy, like that of theHoney bee. Its body is flattened, bulging out prominently at the sides, and tapering more rapidly than usual towards each end of the body. Theskin is very thin, so that along the back the heart or dorsal vessel maybe distinctly seen, pulsating about sixty times a minute. 

Our cut (Fig. 28, _a_) also represents the pupa, or chrysalis, as seenlying in its cell. The limbs are folded close to the body in the mostcompact way possible. On the head of the semi-pupa, _i. E. _, a transitionstate between the larva and pupa, there are two prominent tuberclessituated behind the simple eyes, or ocelli; these are deciduous organs, apparently aiding the insect in moving about its cell. They disappear inthe mature pupa. 

[Illustration: Fig. 29. Fig. 30. Fig. 31. 

Fig. 31. Larva of Halictus parallelus. 

Fig. 29. Larva of Andrena vicina. 

Fig. 30. Pupa of Halictus parallelus seen from beneath. ]

To those accustomed to rearing butterflies, and seeing the chrysalis atonce assuming its perfected shape, after the caterpillar skin is thrownoff, it may seem strange to hear one speak of a "half-pupa, " and ofstages intermediate between the larva and pupa. But the external changesof form, though rapidly passed through, consisting apparently of a meresloughing off of the outer skin, are yet preceded by slow and verygradual alterations of tissues, resulting from the growth of cells. Aninner layer of the larva-skin separates from the outer, and, by changesin the form of the muscles, is drawn into different positions, such asis assumed by the pupa, which thus lies concealed beneath thelarva-skin. But a slight alteration is made in the general form of thelarva, consisting mostly of an enlargement of the thoracic segments, which is often overlooked, even by the special student, though of greatinterest to the philosophic naturalist. 

From Mr. Emerton's observations we should judge that the pupa statelasted from three to four weeks, as the larvæ began to transform thefirst of August, and appeared during the last week of the same month asperfect bees. 

The Andrena is seen as late as the first week in September, and againearly in April, about the flowers of the willow. It is one of thelargest of its genus and a common species. 

Having, in a very fragmentary way, sketched the life history of ourAndrena and had some glimpses of its subterranean life, let us nowcompare with it another genus of solitary bee (Halictus), quite closelyallied in all respects, though a little lower in the scale. 

The Halictus parallelus excavates cells almost exactly like those ofAndrena; but since the bee is smaller, the holes are smaller, though asdeep. Mr. Emerton found one nest in a path a foot in depth. Anothernest, discovered September 9th, was about six inches deep. The cells arein form like those of Andrena, and like them, are glazed within. The eggis rather slenderer and much curved; in form it is long, cylindrical, obtuse at one end, and much smaller at the other. The larva (Fig. 31) islonger and slenderer, being quite different from the rather broad andflattened larva of Andrena. The body is rather thick behind, but infront tapers slowly towards the head, which is of moderate size. Itsbody is somewhat tuberculated, the tubercle aiding the grub in movingabout its cell. Its length is nearly one-half (. 40) of an inch. On thepupa are four quite distinct conical tubercles forming a transverse linejust in front of the ocelli; and there are also two larger, longertubercles, on the outer side of each of which, an ocellus is situated. Figure 30 represents the pupa seen from beneath. 

Search was made on July 16th, where the ground was hard as stone for sixinches in depth, below which the soil was soft and fine, and over twentycells were dug out. "The upper cells contained nearly mature pupæ, andthe lower ones, larvæ of various sizes, the smallest being hardlydistinguishable by the naked eye. Each of these small larvæ was in acell by itself, and situated upon a lump of pollen, which was the sizeand shape of a pea, and was found to lessen in size as the larva grewlarger. These young were probably the offspring of several females, asfour mature bees were found in the hole. " The larva of an Englishspecies hatches in ten days after the eggs are laid. 

Another brood of bees appeared the middle of September, as on the ninthof that month (1864) Mr. Emerton found several holes of the same speciesof bee, made in a hard gravel road near the turnpike. When opened, theywere found to contain several bees with their young. September 2nd, ofthis year, the same kind of bee was found in holes, and just ready toleave the cell. It is probable that these bees winter over. 

We have incidentally noticed the presence in the nests of Andrena andHalictus of a stranger bee, clad in gay, fantastic hues, which lives aparasitic life on its hosts. This parasitism does not go far enough tocause the death of the host, since we find the young of the parasiticCuckoo bee, in cells containing the young of the former. 

Mr. F. Smith, in his "Catalogue of British Bees, " says of this genus:"No one appears to know anything beyond the mere fact of their enteringthe burrows of Andrenidæ and Apidæ, except that they are found in thecells of the working bees in their perfect condition: it is mostprobable that they deposit their eggs on the provision laid up by theworking bee, that they close up the cell, and that the working bee, finding an egg deposited, commences a fresh cell for her own progeny. "

He has, however, found two specimens of Nomada, sexfasciata in the cellsof the long-horned bee, Eucera longicornis. He also states, that whilesome species are constant in their attacks on certain Halicti andAndrenæ, others attack different species of these generaindiscriminately. In like manner another Cuckoo bee (Coelioxys) isparasitic on Megachile and Saropoda; Stelis is a parasite on Osmia, theMason bee: and Melecta infests the cells of Anthophora. 

The observations of Mr. Emerton enable us still further to clear up thehistory of this obscure visitor. He found both the larva and pupa, aswell as the perfect bee, in the cells of both genera; so that eitherboth kinds of bee, when hatched from eggs laid in the same cell, feed onthe same pollen mass, which therefore barely suffices for thenourishment of both; or the hostess, discovering the strange egg laid, cuckoo-like, in her own nest, has the forethought to deposit anotherball of pollen to secure the safety of her young. 

Is such an act the operation of a blind instinct? Does it not ratherally our little bee with those higher animals which undoubtedly possessa reasoning power? Its _instinct_ teaches it to build cells, and prepareits pollen mass, and lay an egg thereon. Its _reason_ enables it, insuch an instance as this, when the life of the brood is threatened, toguard against any such danger by means to which it does not habituallyresort. This instance is paralleled by the case of our common summerYellow bird, which, on finding an egg of the Cow bunting in its nest, often builds a new nest above it, to the certain destruction of theunwelcome egg in the nest beneath. 

In the structure of the bee, and in all its stages of growth, ourparasite seems lower in the zoölogical scale than its host. It isstructurally a degraded form of Working-bee, and its position sociallyis unenviable. It is lazy, not having the provident habits of theWorking-bees; it aids not in the least, so far as we know, thecross-fertilization of plants--one great office in the economy of naturewhich most bees perform, --since it is not a pollen-gatherer, but on thecontrary is seemingly a drag and hinderance to the course of nature. Butyet nature kindly, and as if by a special interposition, provides forits maintenance, and the humble naturalist can only exclaim, "God isgreat, and his ways mysterious, " and go on studying and collectingfacts, leaving to his successors the more difficult task, but greaterjoy of discovering the cause and reason of things that are but a puzzleto the philosophers of this day. 

The larva of Nomada may be known from those of its host, by itsslenderer body and smaller head, while the body is smoother and morecylindrical. Both sexes of Nomada imbricata and N. Pulchella were foundby Mr. Emerton, the former in both the Andrena and Halictus nests, andboth were found in a single Andrena nest. 

[Illustration: Wood Wasp. ]

CHAPTER III. 

THE PARASITES OF THE HONEY BEE. 

Very few bee-keepers are probably aware how many insect parasites infestthe Honey bee. In our own literature we hear almost nothing of thissubject, but in Europe much has been written on bee parasites. From Dr. Edward Assmuss' little work on the "Parasites of the Honey Bee, " weglean some of the facts now presented, and which cannot fail to interestthe general reader as well as the owner of bees. 

The study of the habits of animal parasites has of late gained muchattention among naturalists, and both the honey and wild bees affordgood examples of the singular relation between the host and theparasites which live upon it. Among insects generally, there are certainspecies which devour the contents of the egg of the victim. Others, andthis is the most common mode of parasitism, attack the insect in itslarva state; others, in the pupa state, and still others in the perfect, or imago state. Dr. Leidy has shown that the wood-devouring species ofbeetle, Passalus cornutus, and some Myriopods, or "thousand legs, " are, in some cases, tenanted by myriads of microscopic plants and worms whichluxuriate in the alimentary canal, while the "caterpillar-fungus"attacks sickly caterpillars, filling out their bodies, and sending outshoots into the air, so that the insect looks as if transformed into avegetable. 

The Ichneumon flies, of which there are undoubtedly several thousandspecies in this country, are the most common insect parasites. Next tothese are the different species of Tachina and its allied genera. These, like Ichneumons, live in the bodies of their hosts, consuming the fattyparts, and finishing their transformations just as the exhausted hostis ready to die, issue from their bodies as flies, closely resemblingthe common housefly. 

A small fly has been found in Europe to be the most formidable foe ofthe hive bee, sometimes producing the well-known disease called"foul-brood, " which is analogous to the typhus fever of man. 

[Illustration: 32. Phora and its Young. ]

This fly, belonging to the genus Phora (Fig. 32, Phora incrassata; _a_, larva; _b_, puparium; _c_, another species from Mammoth Cave), is asmall insect about a line and a half long, and found in Europe duringthe summer and autumn flying slowly about flowers and windows, and inthe vicinity of beehives. Its white, transparent larva is cylindrical, alittle pointed before, but broader behind. The head is small androunded, with short, three-jointed antennæ, and at the posterior end ofthe body are several slender spines. The puparium, or pupa case, inclosing the delicate chrysalis, is oval, consisting of eight segments, flattened above, with two large spines near the head, and four on theextremity of the body. 

When impelled by instinct to provide for the continuance of its species, the Phora enters the beehive and gains admission to a cell, when itbores with its ovipositor through the skin of the bee larva, laying itslong oval egg in a horizontal position just under the skin. The embryoof the Phora is already well developed, so that in three hours after theegg is inserted in the body of its unsuspecting and helpless host, theembryo is nearly ready to hatch. In about two hours more it actuallybreaks off the larger end of the egg-shell and at once begins to eat thefatty tissues of its victim, its posterior half still remaining in theshell. In an hour more, it leaves the egg entirely and buries itselfcompletely in the fatty portion of the young bee. 

The maggot moults three times. In twelve hours after the last moult itturns around with its head towards the posterior end of the body of itshost, and in another twelve hours, having become full-fed, it boresthrough the skin of the young, eats its way through the brood-coveringof the cell and falls to the bottom of the hive, where it changes to apupa in the dust and dirt, or else creeps out of the door and transformsin the earth. Twelve days after, the fly appears. 

The young bee, emaciated and enfeebled by the attacks of its ravenousparasite, dies, and its decaying body fills the bottom of the cell witha slimy, foul-smelling mass, called "foul-brood. " This gives rise to amiasma which poisons the neighboring brood, until the contagion (for thedisease is analogous to typhus, jail or ship-fever) spreads through thewhole hive, unless promptly checked by removing the cause and thoroughlycleansing the hive. 

Foul-brood sometimes attacks our American hives, and, though the causemay not be known, yet from the hints given above we hope to have thehistory of our species of Phora cleared up, should our disease be foundto be sometimes due to the attacks of such a parasitic fly. 

[Illustration: 33. Bee Louse and Larva. ]

We figure the Bee louse of Europe (Fig. 33 b, Braula cæca), which is asingular wingless spider-like fly, allied to the wingless Sheep tick(Melophagus), the wingless Bat tick (Nycteribia) and the winged Horsefly (Hippobosca). The head is very large, without eyes or ocelli (simpleeyes), while the ovate hind-body consists of five segments, and iscovered with stiff hairs. It is one-half to two-thirds of a line long. This spider fly is "pupiparous, " that is, the young, of which only avery few are produced, is not born until it has assumed the pupa stateor is just about to do so. The larva (Fig. 33 _a_) is oval, eleven-jointed, and white in color. The very day it is hatched, it shedsits skin and changes to an oval puparium of a dark brown color. 

Its habits resemble those of the flea. Indeed, should we compress itsbody strongly, it would bear a striking resemblance to that insect. Itis evidently a connecting link between the flea, and the two wingedflies. Like the former it lives on the body of its host, and obtains itsfood by plunging its stout beak into the bee and sucking its blood. 

It has not been noticed in this country, but is liable to be imported onthe bodies of Italian bees. Generally, one or two of the Braulas may, onclose examination, be detected on the body of the bee; sometimes thepoor bees are loaded down by as many as a hundred of these hungryblood-suckers. Assmuss recommends rubbing them off with a feather, asthe bee goes in and out of the door of its hive. 

[Illustration: 34. Hive Trichodes. ]

Among the beetles are a few forms occasionally found in bees' nests andalso parasitic on the body of the bee. Trichodes apiarius (Fig. 34, _a_, larva; _b_, pupa, front view) has long been known in Europe to attackthe young bees. In its perfect, or beetle state it is found on flowers, like our Trichodes Nuttallii, which is commonly found on the Spiræa inAugust, and which may yet prove to enter our beehives. The larva devoursthe brood, but with the modern hive its ravages may be readily detected. 

[Illustration: 35. Meloë. ]

The Oil beetle, Meloë angusticollis (Fig. 35, male, differing from thefemale by having the antennæ as if twisted into a knot; Fig. 36, theactive larva found on the body of the bee), is a large dark blue insectfound crawling in the grass in the vicinity of the nests of Andrena, Halictus, and other wild bees in May, and again in August andSeptember. The eggs are laid in a mass covered with earth at the rootof some plant. During April and early in May, when the willows are inblossom, we have found the young recently hatched larvæ in considerableabundance creeping briskly over the bees, or with their heads plungedbetween the segments of the body, greedily sucking in the juices oftheir host. Those that we saw occurred on the Humble and other wildbees, and on various flies (Syrphus and Muscidæ), and there is no reasonwhy they should not infest the Honey bee, which frequents similarflowers, as they are actually known to do in Europe. These larvæ areprobably hatched out near where the bees hibernate, so as to creep intotheir bodies before they fly in the spring, as it would be impossiblefor them to crawl up a willow tree ten feet high or more, their feetbeing solely adapted for climbing over the hairy body of the bee, whichthey do not leave until about to undergo their strange and unusualtransformations. 

[Illustration: Early Stages of Meloë. ]

In Europe, Assmuss states that on being brought into the nest by thebee, they leave the bee and devour the eggs in the bee cells, and thenattack the bee bread. When full-fed and ready to pass through theirtransformations to attain the beetle state, instead of at once assumingthe pupa and imago forms, as in the Trichodes represented in fig. 34, they pass through a _hyper-metamorphosis_, as Fabre, a Frenchnaturalist, calls it. In other words, the changes in form which arepreparatory to assuming the pupa and imago states are more marked andalmost coequal with the larva and pupa states, so that the Meloë, instead of passing through three states (the egg, larva and pupa), inrealty passes through these and two others in addition, which areintermediate. The whole subject of the metamorphosis of this beetleneeds revision, but Fabre states that the larva, soon after entering thenest of its host, changes its skin and assumes a second larva form. Newport, who with Siebold has carefully described the metamorphoses ofMeloë, does not mention this stage in its development, which Fabre calls"pseudo-chrysalis. " It is motionless, the head is mask-like, withoutmovable appendages, and the feet are represented by six tubercles. Thisis more properly speaking the semi-pupa, and the mature pupa growsbeneath its mask-like form, which is finally moulted. This form, however, according to Fabre, changes its skin and turns into a thirdlarva form (Fig. 37). After some time it assumes its true pupa form(Fig. 38), and finally moults this skin to appear as a beetle. 

Fabre has also, in a lively and well-written account, given a history ofSitaris, a European beetle, somewhat resembling Meloë. He states thatSitaris lays its eggs near the entrance of bees' nests, and at the verymoment that the bee lays her egg in the honey cell, the flattened, ovateSitaris larva drops from the body of the bee upon which it has beenliving, and feasts upon the contents of the freshly laid egg. Aftereating this delicate morsel it devours the honey in the cells of the beeand changes into a white, cylindrical, nearly footless grub, and afterit is full-fed, and has assumed a supposed "pupa" state, the skin, without bursting, incloses a kind of hard "pupa" skin, which is verysimilar in outline to the former larva, within whose skin is found awhitish larva which directly changes into the true pupa. In a succeedingstate this pupa in the ordinary way changes to a beetle which belongs tothe same group of Coleoptera as Meloë. We cannot but think, fromobservations made on the humble bee, the wasp, two species of moths andseveral other insects, that this "hyper-metamorphosis" is not soabnormal a mode of insect metamorphosis as has been supposed, and thatthe changes of these insects, made beneath the skin of the mature larvabefore assuming the pupa state, are almost as remarkable as those ofMeloë and Sitaris, though less easily observed than they. Several otherbeetles allied to Meloë are known to be parasitic on wild bees, thoughthe accounts of them are fragmentary. 

THE STYLOPS PARASITE. 

The history of Stylops, a beetle allied to Meloë, is no less strangethan that of Meloë, and is in some respects still more interesting. OnJune 18th I captured an Andrena vicina which had been "stylopized. " Onlooking at my capture I saw a pale reddish-brown triangular mark on thebee's abdomen; this was the flattened head and thorax of a femaleStylops (Fig. 39_a_, position of the female of Stylops, seen in profilein the abdomen of the bee; Fig. 39_b_, the female seen from above. Thehead and thorax are soldered into a single flattened mass, the baggyhind-body being greatly enlarged like that of the gravid female of thewhite ant, and consisting of nine segments). 

[Illustration: 39. Female Stylops. ]

On carefully drawing out the whole body (Pl. 1, Fig. 6, as seen fromabove, and showing the alimentary canal ending in a blind sac; Fig. 6_a_, side view), which is very extensible, soft and baggy, andexamining it under a high power of the microscope, we saw multitudes, atleast several hundred, of very minute larvæ, like particles of dust tothe naked eye, issuing in every direction from the body of the parentnow torn open in places, though most of them made their exit through anopening on the under side of the head-thorax. The Stylops, being hatchedwhile still in the body of the parent, is, therefore viviparous. Sheprobably never lays eggs. 

On the last of April, when the Mezereon was in blossom, I caught thesingular looking male (Stylops Childreni, Fig. 40; a, side view; it isabout one-fourth of an inch long), which was as unlike its partner aspossible. I laid it under a tumbler, when the delicate insect flew andtumbled about till it died of exhaustion in a few hours. 

It appears, then, that the larvæ are hatched during the middle or lastof June from eggs fertilized in April. The larvæ then crawl out upon thebody of the bee, on which they are transported to the nest, where theyenter, according to Peck's observations, the body of the larva, on whosefatty parts they feed. Previous to changing to a pupa the larva liveswith its head turned towards that of its host, but before assuming theperfect state (which they do in the late summer or autumn) it mustreverse its position. The female protrudes the front part of her bodybetween the segments of the abdomen of her host, as represented in ourfigure. This change, Newport thinks, takes place after the bee-host hasundergone its metamorphoses, though the bee does not leave her earthencells until the following spring. Though the male Stylops deserts hishost, his wingless partner is imprisoned during her whole life withinher host, and dies immediately after giving birth to her myriad (forNewport thinks she produces over two thousand) offspring. 

[Illustration: 40. Male Stylops. ]

Xenos Peckii, an allied insect, was discovered by Dr. Peck to beparasitic in the body of wasps, and there are now known to be severalspecies of this small but curious family, Stylopidæ, which are known tolive parasitically on the bodies of our wild bees and wasps. Thepresence of these parasites finally exhausts the host, so that thesterile female bee dies prematurely. 

As in the higher animals, bees are afflicted with parasitic worms whichinduce disease and sometimes death. The well-known hair worm, Gordius, is an insect parasite. The adult form is about the size of a slenderknitting needle, and is seen in moist soil and in pools. It lays, according to Dr. Leidy, "millions of eggs connected together in longcords. " The microscopical, tadpole-shaped young penetrate into thebodies of insects frequenting damp localities. Fairly ensconced withinthe body of their unsuspecting host, they luxuriate on its fattytissues, and pass through their metamorphoses into the adult form, whenthey desert their living house and take to the water to lay their eggs. In Europe, Siebold has described Gordius subbifurcus, which infests thedrones of the Honey bee, and also other insects. Professor Siebold hasalso described Mermis albicans, which is a similar kind of hair worm, from two to five inches long, and whitish in color. This worm is alsofound, strangely enough, only in the drones, though it is the workerswhich frequent watery places to appease their thirst. 

[Illustration: 41. Bee fungus. ]

Thousands of insects are carried off yearly by parasitic fungi. Theravages of the Muscardine, caused by a minute fungus (BotrytrisBassiana), have threatened the extinction of silk culture in Europe, andthe still more formidable disease called _pebrine_ is thought to be ofvegetable origin. Dr. Leidy mentions a fungus which must annually carryoff myriads of the Seventeen Year Locust. A somewhat similar fungus, Mucor mellitophorus (Fig. 41), infests bees, filling the stomach withmicroscopical colorless spores, so as greatly to weaken the insect. 

As there is a probability that many insects, parasites on the wild bees, may sooner or later afflict the Honey bee, and also to illustratefarther the complex nature of insect parasitism, we will for a momentlook at some other bee parasites. 

[Illustration: Pl. 1

PARASITES OF BEES. ]

Among the numerous insects preying in some way upon the Humble bee areto be found other species of bees and moths, flies and beetles. Insectparasites often imitate their host: Apathus (Plate I, Fig. 1, A. Ashtoni) can scarcely be distinguished from its host, and yet it livescuckoo-like in the cells of the Humble bee, though we know not yet howinjurious it really is. Then there are Conops and Volucella, theformer of which lives like Tachina and Phora within the bee's body, while the latter devours the brood. The young (Plate I, Figs. 5, 5_a_)of another fly allied to Anthomyia, of which the Onion fly (Fig. 42) isan example, is also not unfrequently met with. A small beetle (Plate 1. Fig. 4, Antherophagus ochraceus) is a common inmate of Humble bees'nests, and probably feeds upon the wax and pollen. We have also foundseveral larvæ (Fig. 43) of a beetle of which we do not know the adultform. Of similar habits is probably a small moth (Nephopteryx Edmandsii, Plate I, Figs. 2; 2_a_, larva; Fig. 2_b_, chrysalis, or pupa) whichundoubtedly feeds upon the waxen walls of the bee cells, and thus, likethe attacks of the common bee moth (Galleria cereana, whose habits areso well known as not to detain us, must prove very prejudicial to thewell being of the colony. This moth is in turn infested by an Ichneumonfly (Microgaster nephoptericis, Plate I, Figs. 3, 3_a_) which must provequite destructive. 

[Illustration: 42. Onion Fly and Maggot. ]

[Illustration: 43. Larva of Beetle. ]

The figures of the early stages of a minute ichneumon represented on thesame plate (Fig. 7, larva, and 7_a_, pupa, of Anthophorabia megachilis)which is parasitic on Megachile, the Leaf-cutter bee, illustrates thetransformations of the Ichneumon flies, the smallest species of whichyet known (and we believe the smallest insect known at all) is thePteratomus Putnami (Pl. I, Fig. 8, wanting the hind leg), or "wingedatom, " which is only one-ninetieth of an inch in length, and isparasitic on Anthophorabia, itself a parasite. A species of mite (PlateI, Figs. 9; 9_a_, the same seen from beneath) is always to be found Inhumble bees' nests, but it is not thought to be specially obnoxious tothe bees themselves, though several species of mites (Gamasus, etc. ) areknown to be parasitic on insects. 

CHAPTER IV. 

A FEW WORDS ABOUT MOTHS. 

The butterflies and moths from their beauty and grace, have always beenthe favorites among amateur entomologists, and rare and costly workshave been published in which their forms and gorgeous colors arerepresented in the best style of natural history art. We need onlymention the folio volume of Madam Merian of the last century, Harris'sAurelian, the works of Cramer, Stoll, Drury, Hübner, Horsfield, Doubleday and Westwood, and Hewitson, as comprising the most luxuriousand costly entomological works. 

Near the close of the last century, John Abbot went from London andspent several years in Georgia, rearing the larger and more showybutterflies and moths, and painting them in the larva, chrysalis andadult, or imago stage. These drawings he sent to London to be sold. Manyof them were collected by Sir James Edward Smith, and published underthe title of "The Natural History of the Rarer Lepidopterous Insects ofGeorgia, collected from the Observations of John Abbot, with the Plantson which they Feed. " (London, 1797. 2 vols. , fol. ) Besides these tworare volumes there are sixteen folio volumes of drawings by Abbot in theLibrary of the British Museum. This work is of especial interest to theAmerican student as it illustrates the early stages of many of ourbutterflies and moths. 

Indeed the study of insects possesses most of its interest when weobserve their habits and transformations. Caterpillars are always to befound, and with a little practice are easy to raise; we would thereforeadvise any one desirous of beginning the study of insects to take up thebutterflies and moths. They are perhaps easier to study than any othergroup of insects, and are more ornamental in the cabinet. As ascientific study we would recommend it to ladies as next to botany ininterest and in the ease in which specimens may be collected andexamined. The example of Madam Merian, and several ladies in thiscountry who have greatly aided science by their well filled cabinets, and critical knowledge of the various species and their transformations, is an earnest of what may be expected from their followers. Though themoths are easy to study compared with the bees, flies, beetles and bugs, and dragon flies, yet many questions of great interest in philosophicalentomology have been answered by our knowledge of their structure andmode of growth. The great works of Herold on the evolution of acaterpillar; of Lyonet on the anatomy of the Cossus; of Newport on thatof the Sphinx; and of Siebold on the parthenogenesis of insects, areproofs that the moths have engaged the attention of some of the masterminds in science. 

The study of the transformations of the moths is also of greatimportance to one who would acquaint himself with the questionsconcerning the growth and metamorphoses and origin of animals. We shouldremember that the very words "metamorphosis" and "transformation, " nowso generally applied to other groups of animals and used inphilosophical botany, were first suggested by those who observed thatthe moth and butterfly attain their maturity only by passing throughwonderful changes of form and modes of life. 

The knowledge of the fact that all animals pass through some sort of ametamorphosis is very recent in physiology. Moreover the fact that thesemorphological eras in the life of an individual animal accord mostunerringly with the gradation of forms in the type of which it is amember, was the discovery of the eminent physiologist Von Baer. Up tothis time the true significance of the luxuriance and diversity oflarval forms had never seriously engaged the attention of systematistsin entomology. 

What can possibly be the meaning of all this putting on and taking offof caterpillar habiliments, or in other words, the process of moulting, with the frequent changes in ornamentation, and the seemingfastidiousness and queer fancies and strange conceits of these young andgiddy insects seems hidden and mysterious to human observation. Indeed, few care to spend the time and trouble necessary to observe the insectthrough its transformations; and that done, if only the larva of theperfect insect can be identified and its form sketched how much wasgained! A truthful and circumstantial biography, in all its relations, of a single insect has yet to be written!

We should also apply our knowledge of the larval forms of insects to thedetails of their classification into families and genera, constantlycollating our knowledge of the early stages with the structuralrelations that accompany them in the perfect state. 

The simple form of the caterpillar seems to be a concentration of thecharacters of the perfect insect, and presents easy characters by whichto distinguish the minor groups; and the relative rank of the higherdivisions will only be definitely settled when their forms and methodsof transformation are thoroughly known. Thus, for example, in two groupsof the large Attacus-like moths, which are so amply illustrated in Dr. Harris's "Treatise on Insects injurious to Vegetation"; if we take thedifferent forms of the caterpillars of the Tau moth of Europe, which arefigured by Duponchel and Godard, we find that the very young larva hasfour horn-like processes on the front, and four on the back part of thebody. The full grown larva of the Regalis moth, of the Southern andMiddle states, is very similarly ornamented. It is an embryonic form, and therefore inferior in rank to the Tau moth. Multiply these hornsover the surface of the body, lessen their size, and crown them withhairs, and we have our Io moth, so destructive to corn. Now take off thehairs, elongating and thinning out the tubercles, and make up the lossby the increased size of the worm, and we have the caterpillar of ourcommon Cecropia moth. Again, remove the naked tubercles almost wholly, smooth off the surface of the body, and contract its length, thus givinga greater convexity and angularity to the rings, and we have before usthe larva of the stately Luna moth that tops this royal family. Here arecertain criteria for placing these insects before our minds in the orderthat nature has placed them. We have certain facts for determining whichof these three insects is highest and which lowest in the scale, when wesee the larva of the Luna moth throwing off successively the Io andCecropia forms to take on its own higher features. So that there is ameaning in all this shifting of insect toggery. 

This is but an example of the many ways in which both pleasure andmental profit may be realized from the thoughtful study of caterpillarlife. 

In collecting butterflies and moths for cabinet specimens, one needs agauze net a foot and a half deep, with the wire frame a foot indiameter; a wide-mouthed bottle containing a parcel of cyanide ofpotassium gummed on the side, in which to kill the moths, which should, as soon as life is extinct, be pinned in a cork-lined collecting boxcarried in the coat pocket. The captures should then be spread and driedon a grooved setting board, and a cabinet formed of cork-lined boxes ordrawers; as a substitute for cork, frames with paper tightly stretchedover them may be used, or the pith of corn-stalks or palm wood. Caterpillars should be preserved in spirits, or in glycerine with alittle alcohol added. 

Some persons ingeniously empty the skins and inflate them over a flameso that they may be pinned by the side of the adult. 

Some of the most troublesome and noxious insects are found among themoths. I need only mention the canker worm and American tentcaterpillar, and the various kinds of cut worms, as instances. 

[Illustration: 43. Parasite of the American Silk Worm. ]

We must not, however, forget the good done by insects. They undoubtedlytend by their attacks to prevent an undue growth of vegetation. Thepruning done to a tree or herb by certain insects undoubtedly causes amore healthy growth of the branches and leaves, and ultimately a greaterproduction fruit. Again, as pollen-bearers, insects are a most powerfulagency in nature. It is undoubtedly the fact that the presence, of beesin orchards increases the fruit crop, and thus the thousands of moths(though injurious as caterpillars), wild bees and other insects, thatseem to live without purpose, are really, though few realize it, amongthe best friends and allies of man. 

Moreover, insects are of great use as scavengers; such are the young ormaggots of the house fly, the mosquitoes, and numerous other forms, thatseem created only to vex us when in the winged state. Still a largerproportion of insects are directly beneficial from their habit ofattacking injurious species, such as the ichneumons (Fig. 43, theichneumon of the American silk worm) and certain flies (Fig. 44, Tachina); also many carnivorous species of wasps beetles and flies, dragon flies and Aphis lions (Fig. 45, the lace-winged fly; adult, larvaand eggs). 

[Illustration: 44. Tachina, parasite of Colorado Potato Beetle. ]

[Illustration: 45. The Lace-winged Fly, Its Larva and Eggs. ]

But few, however, suspect how enormous are the losses to crops in thiscountry entailed by the attacks of the injurious species. In Europe, thesubject of applied entomology has always attracted a great deal ofattention. Most sumptuous works, elegant quartos prepared by naturalistsknown the world over, and published at government expense, together withsmaller treatises, have frequently appeared; while the subject is taughtin the numerous agricultural colleges and schools, especially ofGermany. 

In the densely populated countries of Europe, the losses occasioned byinjurious insects are most severely felt, though from many causes, suchas the greater abundance of their insect parasites, and the far greatercare taken by the people to exterminate their insect enemies, they havenot proved so destructive as in our own land. 

In this connection I may quote from one of Dr. Asa Fitch's reports onthe noxious insects of New York, where he says: "I find that in ourwheat-fields here, the midge formed 59 per cent. Of all the insects onthis grain the past summer; whilst in France, the preceding summer, only7 per cent. Of the insects on wheat were of this species. In France theparasitic destroyers amounted to 85 per cent. ; while in this country ourparasites form only 10 per cent. "

"A true knowledge of practical entomology may well be said to be in itsinfancy in our own country, when, as is well-known to agriculturists, the cultivation of wheat has almost been given up in New England, NewYork, Pennsylvania, Ohio and Virginia, from the attacks of the wheatmidge, Hessian fly, joint worm, and chinch bug. According to Dr. Shimer's estimate, says Mr. Riley, in his Second Annual Report on theInjurious Insects of Missouri, which may be considered a reasonableone, in the year 1864 three-fourths of the wheat, and one-half of thecorn crop were destroyed by the chinch bug throughout many extensivedistricts, comprising almost the entire North-West. At the annual rateof increase, according to the United States Census, in the State ofIllinois, the wheat crop ought to have been about thirty millions ofbushels, and the corn crop about one hundred and thirty-eight millionbushels. Putting the cash value of wheat at $1. 25, and that of corn at50 cents, the cash value of the corn and wheat destroyed by thisinsignificant little bug, no bigger than a grain of rice, in one singleState and one single year, will therefore, according to the abovefigures, foot up to the astounding total of _over seventy-three millionsof dollars_!"

The imported cabbage butterfly (Pieris rapæ), recently introduced fromEurope, is estimated by the Abbé Provatncher, a Canadian entomologist, to destroy annually two hundred and forty thousand dollars' worth ofcabbages around Quebec. The Hessian fly, according to Dr. Fitch, destroyed fifteen million dollars' worth of wheat in New York State inone year (1854). The army worm of the North (Leucania unipuncta), whichwas so abundant in 1861, from New England to Kansas, was reported tohave done damage that year in Eastern Massachusetts exceeding half amillion of dollars. The joint worm (Isosoma hordei) alone sometimes cutsoff whole fields of grain in Virginia and northward. The Colorado potatobeetle is steadily moving eastward, now ravaging the fields in Indianaand Ohio, and only the forethought and ingenuity in devising means ofchecking its attacks, resulting from a thorough study of its habits, will deliver our wasted fields from its direful assaults. 

These are the injuries done by the more abundant kinds of insectsinjurious to crops. We should not forget that each fruit or shade tree, garden shrub or vegetable, has a host of insects peculiar to it, andwhich, year after year, renew their attacks. I could enumerate upwardsof fifty species of insects which prey upon cereals and grass, and asmany which infest our field crops. Some thirty well known species ravageour garden vegetables. There are nearly fifty species which attack thegrape vine, and their number is rapidly increasing. About seventy-fivespecies make their annual onset upon the apple tree, and nearly an equalnumber may be found upon the plum, pear, peach and cherry. Among ourshade trees, over fifty species infest the oak; twenty-five the elm;seventy-five the walnut, and over one hundred species of insects preyupon the pine. 

Indeed, we may reasonably calculate the annual loss in our countryalone, from noxious animals and the lower forms of plants, such as rust, smut and mildew, as (at a low estimate) not far from five hundredmillion dollars annually. Of this amount, at least one-tenth, or fiftymillion dollars, could probably be saved by human exertions. 

To save a portion of this annual loss of food stuffs, fruits and lumber, should be the first object of farmers and gardeners. When this saving ismade, farming will become a profitable and safe profession. But while afew are well informed as to the losses sustained by injurious insects, and use means to ward off their attacks, their efforts are constantlyfoiled by the negligence of their neighbors. As illustrated so well bythe history of the incursions of the army worm and canker worm, it isonly by a combination between farmers and orchardists that these andother pests can be kept under. The matter can be best reached bylegislation. We have fish and game laws; why should we not have aninsect law? Why should we not frame a law providing that farmers, andall owning a garden or orchard, should cooperate in taking preventivemeasures against injurious insects, such as early or late planting ofcereals, to avert the attacks of the wheat midge and Hessian fly; theburning of stubble in the autumn and spring to destroy the joint worm;the combined use of proper remedies against the canker worm, thevarious cut worms, and other noxious caterpillars? A law carried out bya proper State entomological constabulary, if it may be so designated, would compel the idle and shiftless to clear their farms and gardens ofnoxious animals. 

[Illustration: 46. Pickle Worm and its Moth. ]

Among some of the injurious insects reported on by Mr. Riley, the StateEntomologist of Missouri, is a new pest to the cucumber in the West, thePickle worm (Phacellura nitidalis, Fig. 46). This is a caterpillar whichbores into the cucumbers when large enough to pickle, and which isoccasionally found in pickles. Three or four worms sometimes occur in acucumber, and in the garden a single one will cause it to rot. One ofthe most troublesome intruders in our graperies is the Vine dresser(Choerocampa pampinatrix, Fig. 47, larva and pupa; Fig. 48, adult), asingle caterpillar of which will sometimes "strip a small vine of itsleaves in a few nights, " and occasionally nips off bunches of half-growngrapes. 

[Illustration: 48. Vine Dresser Moth. 

47. Vine Dresser and Chrysalis. ]

Another caterpillar, which is sometimes so abundant as nearly todefoliate the grape vine, is the eight spotted Alypia (Fig. 49; _a_, larva; _b_, side view of a segment). This must not be confounded withthe bluish larva of the Wood Nymph, Eudryas grata (Fig. 50), whichdiffers from the Alypia caterpillar in being bluish, and in wanting thewhite patches on the side of the body, and the more prominent hump onthe end of the body. Another moth (Psychomorpha epimenis, Fig. 51, _a_, larva; _b_, side view of a segment; _c_, top view of the hump), also feeds on the grape, eating the terminal buds. It is also bluish, and wants the orange bands on the side of the body. Another moth of thisfamily is the American Procris (Acoloithus Americana, Fig. 52_a_, larva;_b_, pupa; _c_, cocoon; _d_, _e_, imago); a dark blue moth, with a deeporange collar, whose black and yellow caterpillar is gregarious (Fig. 53), living in companies of a dozen or more and eating the softer partsof the leaves. It is quite common in the Western and Southern States. The figure represents two separate broods of caterpillars feeding oneither side of the midrib of the leaf. But if the moths are, as a rule, the enemies of our crops, there are the silk worms of the East andSouthern Europe and California, which afford the means of support tomultitudes of the poorer classes, and supply one of the most valuablearticles of clothing. Blot out the silk worm, and we should remove oneof the most important sources of national wealth, the annual revenuefrom the silk trade of the world amounting to $254, 500, 000. 

[Illustration: 49. Eight-spotted Alypia and Larva. ]

[Illustration: 50. Eudryas grata. ]

[Illustration: 51. Larva of Psychomorpha. ]

[Illustration: 52. American Procris and Young. ]

[Illustration: 53. Larvæ of American Procris. ]

Silk culture is rapidly assuming importance in California, and thoughthe Chinese silk worm has not been successfully cultivated in theEastern States, yet the American silk worm, Teleas Polyphemus (seefrontispiece, male; Fig. 54, larva; 55, pupa; 56, cocoon), can, we areassured by Mr. Trouvelot, be made a source of profit. 

This is a splendid member of the group of which the gigantic AttacusAtlas of China is a type. It is a large, fawn colored moth with a tawnytinge; the caterpillar is pale green, and is of the size indicated inthe cut. Mr. Trouvelot says that of the several kinds of silk worms, thelarva of the present species alone deserves attention. The cocoons ofPlatysamia Cecropia may be rendered of some commercial value, as thesilk can be carded, but the chief objection is the difficulty of raisingthe larva. 

"The Polyphemus worm spins a strong, dense, oval cocoon, which is closedat each end, while the silk has a very strong and glossy fibre. " Mr. Trouvelot, from whose interesting account in the first volume of the"American Naturalist" we quote, says that in 1865 "not less than amillion could be seen feeding in the open air upon bushes covered with anet; five acres of woodland were swarming with caterpillar life. " Thebushes were scrub oaks, the worms being protected by a net. Aftermeeting with such great success Mr. Trouvelot lost all his worms bypebrine, the germs being imported in eggs received from Japan through M. Guérin-Méneville of Paris. Enough, however, was done to prove that silkraising can be carried on profitably, when due precautions are taken, asfar north as Boston. As this moth extends to the tropics, it can bereared with greater facility southwards. The cocoon is strong and dense, and closed at each end, so that the thread is continuous, while the silkhas a very strong and glossy fibre. 

[Illustration: 54. American Silk Worm. ]

Next in value to the American silk worm, is the Ailanthus silk worm(Samia Cynthia) a species allied to our Callosamia Promethea. Itoriginated from China, where it is cultivated, and was introduced intoItaly in 1858, and thence spread into France, where it was introduced byM. Guérin-Méneville. Its silk is said to be much stronger than the fibreof cotton, and is a mean between fine wool and ordinary silk. The wormis very hardy, and can be reared in the open air both in this countryand in Europe. The main drawback to its culture is the difficulty inunreeling the tough cocoon, and the shortness of the thread, the cocoonbeing open at one end. 

The Yama-maï moth (Antheræa Yama-maï) was introduced into France fromJapan in 1861. It is closely allied to the Polyphemus moth, and itscaterpillar also feeds on the oak. Its silk is said to be quitebrilliant, but a little coarser and not so strong as that of the Bombyxmori. The Perny silk worm is extensively cultivated by the Chinese inManchouria, where it feeds on the oak. Its silk is coarser than that ofthe common silk worm, but is yet fine, strong and glossy. Bengal hasfurnished the Tussah moth, which lives in India on the oak and a varietyof other trees. It is largely raised in French and English India, according to Nogués, and is used in the manufacture of stuffs calledcorahs. 

[Illustration: 55. Chrysalis of American Silk Worm. ]

[Illustration: 56. Cocoon of American Silk Worm. ]

The last kind of importance is the Arrhindy silk worm, from India. Ithas been naturalized in France and Algeria by M. Guérin-Méneville, whohas done so much in the application of entomology to practical life. Itis closely allied to the Cynthia or Ailanthus worm, with the same kindof silk and a similar cocoon, and feeds on the castor oil plant. 

The diseases of silk worms naturally receive much attention. Like thoseafflicting mankind, they arise from bad air, resulting from too closeconfinement, bad food, and other adverse causes. The most fatal andwide-spread disease, and one which since 1854 has threatened theextermination of silk worms in Europe, is the _pebrine_. It is due tothe presence of minute vegetable corpuscles, which attack both the wormsand the eggs. It was this disease which swept off thousands of Mr. Trouvelot's Polyphemus worms, and put a sudden termination to hisimportant experiments, the germs having been implanted in eggs of theYama-maï moth imported from Japan by M. Guérin-Méneville, and which wereprobably infected as they passed through Paris. Though the disasterhappened several years since, he tells us that it will be useless forhim to attempt the raising of silk worms in the town where hisestablishment is situated, as the germs of the disease are mostdifficult to eradicate. 

So direful in France were the ravages of this disease that two of themost advanced naturalists in France, Quatrefages and Pasteur, werecommissioned by the French government to investigate the disease. Pasteur found that the infected eggs differed in appearance from thesound ones, and could thus be sorted out by aid of the microscope anddestroyed. Thus these investigations, carried on year after year, andseeming to the ignorant to tend to no practical end, resulted in savingto France her silk culture. During the past year (1871) so successfulhas his method proved that a French scientific journal expresses thehope of the complete reestablishment and prosperity of this greatindustry. A single person who obtained in 1871 in his nurseries 30, 000ounces of eggs, hopes the next year to obtain 100, 000 ounces, from whichhe expects to realize about one million dollars. 

[Illustration: The Potato Caterpillar. ]

CHAPTER V. 

THE CLOTHES MOTH. 

For over a fortnight we once enjoyed the company of the caterpillar of acommon clothes moth. It is a little pale, delicate worm (Fig. 57, magnified), about the size of a darning needle, and rather less thanhalf an inch in length, with a pale horn-colored head, the ring next thehead being of the same color. It has sixteen feet, the first six of themwell developed and constantly in use to draw the slender body in and outof its case. Its head is armed with a formidable pair of jaws, withwhich, like a scythe, it mows its way through thick and thin. 

But the case is the most remarkable feature in the history of thiscaterpillar. Hardly has the helpless, tiny worm broken out of the egg, previously laid in some old garment of fur or wool, or perhaps in thehaircloth of a sofa, when it begins to make a shelter by cutting thewoolly fibres or soft hairs into bits, which it places at each end insuccessive layers, and, joining them together by silken threads, constructs a cylindrical tube (Fig. 58) of thick, warm felt, linedwithin with the finest silk the tiny worm can spin. The case is notperfectly cylindrical, being flattened slightly in the middle, andcontracted a little just before each end, both of which are always keptopen. The case before us is of a stone-gray color, with a black stripealong the middle, and with rings of the same color round each opening. Had the caterpillar fed on blue or yellow cloth, the case would, ofcourse, have been of those colors. Other cases, made by larvæ which hadbeen eating loose cotton, were quite irregular in form, and coveredloosely with bits of cotton thread, which the little tailor had nottrimmed off. 

Days go by. A vigorous course of dieting on its feast of wool has givenstature to our hero. His case has grown uncomfortably small. Shall heleave it and make another? No housewife is more prudent and saving. Outcome those scissor-jaws, and, lo! a fearful rent along each side of oneend of the case. Two wedge-shaped patches mend the breach; thecaterpillar retires for a moment and reappears at the other end; thescissors are once more pulled out; two rents appear, to be filled up bytwo more patches or gores, and our caterpillar once again breathes morefreely, laughs and grows fat upon horse hair and lambs' wool. In thisway he enlarges his case till he stops growing. 

[Illustration: 59. 58. 57. 

Early Stages of the Clothes Moth. ]

Our caterpillar seeming to be full-grown, and apparently out ofemployment, we cut the end of his case half off. Two or three daysafter, he had mended it from the inside, drawing the two edges togetherby silken threads, and, though he had not touched the outside, yet soneatly were the two parts joined together that we had to search for sometime, with a lens, to find the scar. 

To keep our friend busy during the cold, cheerless weather, for it wasmid-winter, we next cut a third of the case entirely off. Nothingdaunted, the little fellow bustled about, drew in a mass of the woollyfibres, filling up the whole mouth of his den, and began to build onafresh, and from the inside, so that the new-made portion was smallerthan the rest of the case. The creature worked very slowly, and theaddition was left in a rough, unfinished state. 

We could easily spare these voracious little worms hairs enough to serveas food, and to afford material for the construction of their paltrycases; but that restless spirit that ever urges on all beings endowedwith life and the power of motion, never forsakes the young clothes mothfor a moment. He will not be forced to drag his heavy case over roughhairs and furzy wool, hence with his keen jaws he cuts his way through. Thus, the more he travels, the more mischief he does. 

After taking his fill of this sort of life he changes to a chrysalid(Fig. 59), and soon appears as one of those delicate, tiny, demuremoths that fly in such numbers from early in the spring until theautumn. 

Very many do not recognize these moths in their perfect stage, so smallare they, and vent their wrath on those great millers that fly aroundlamps in warm summer evenings. It need scarcely be said that these largemillers are utterly guiltless of any attempts upon our wardrobes; theymake their attacks in a more open form on our gardens and orchards. 

We will give a more careful description of the clothes moth, which wasfound in its different stages June 12th in a mass of loose cotton. Thelarva is white, with a tolerably plump body, which tapers slightlytowards the tail, while the head is much of the color of gum-copal. Therings of the body are thickened above, especially on the thoracic ones, by two transverse thickened folds. It is one-fifth of an inch long. 

The body of the chrysalis, or pupa, is considerably curved, with thehead smooth and rounded. The long antennæ, together with the hind legs, which are folded along the breast, reach to the tip of the hind body, onthe upper surface of each ring of which is a short transverse row ofminute spines, which aid the chrysalis in moving towards the mouth ofits case, just before the moth appears. At first the chrysalis iswhitish, but just before the exclusion of the moth becomes the color ofvarnish. 

When about to cast its pupa skin, the skin splits open on the back, andthe perfect insect glides out. The act is so quickly over with, that theobserver has to look sharp to observe the different steps in theoperation. 

[Illustration: 60. Clothes Moth. ]

Our common clothes moth (Tinea flavifrontella, Fig. 60) is of a uniformlight-buff color, with a silky iridescent lustre, the hind wings andabdomen being a little paler. The head is thickly tufted with hairs andis a little tawny, and the upper side of the densely hirsute feelers(palpi) is dusky. The wings are long and narrow, with the most beautifuland delicate long silken fringe, which increases in length towards thebase of the wing. 

They begin to fly in May, and last all through the season, flutteringwith a noiseless, stealthy flight in our apartments, and laying theireggs in our woollens. 

Successive broods of the clothes moth appear through the summer. In theautumn they cease eating, retire within their cases, and early in springassume the chrysalis state. 

There are several allied species which have much the same habits, exceptthat they do not all construct cases, but eat carpets, clothing, articles of food, grain, etc. , and objects of natural history. 

Careful housewives are not much afflicted with these pests. The slovenlyand thriftless are overrun with them. Early in June woollens and fursshould be carefully dusted, shaken and beaten. Dr. T. W. Harris statesthat "powdered black pepper, strewed under the edge of carpets, is saidto repel moths. Sheets of paper sprinkled with spirits of turpentine, camphor in coarse powder, leaves of tobacco, or shavings of Russialeather, should be placed among the clothes when they are laid aside forthe summer; and furs and other small articles can be kept by being sewedin bags with bits of camphor wood, red cedar, or of Spanish cedar; whilethe cloth lining of carriages can be secured forever from the attacks ofmoths by being washed or sponged on both sides with a solution of thecorrosive sublimate of mercury in alcohol, made just strong enough notto leave a white stain on a black feather. " The moths can be mostreadily killed by pouring benzine among them, though its use must bemuch restricted from the disagreeable odor which remains. The recentexperiments made with carbolic acid, however, convince us that this willsoon take the place of other substances as a preventive and destroyer ofnoxious insects. 

[Illustration: The Juniper Sickle-wing. ]

CHAPTER VI. 

THE MOSQUITO AND ITS FRIENDS. 

The subject of flies becomes of vast moment to a Pharaoh, whose ears aredinned with the buzz of myriad winged plagues, mingled with angry criesfrom malcontent and fly-pestered subjects; or to the summer traveller innorthern lands, where they oppose a stronger barrier to his explorationsthan the loftiest mountains or the broadest streams; or to the Africanpioneer, whose cattle, his main dependence, are stung to death by theTsetze fly; or the fariner whose eyes on the evening of a warm springday, after a placid contemplation of his growing acres of wheat blades, suddenly detects in dismay clouds of the Wheat midge and Hessian flyhovering over their swaying tops. The subject, indeed, has in such casesa national importance, and a few words regarding the main points in thehabits of flies--how they grow, how they do not grow (after assuming thewinged state), and how they bite; for who has not endured the smart andsting of these dipterous Shylocks, that almost torment us out of ourexistence while taking their drop of our heart's blood--may be welcome toour readers. 

[Illustration: 61. Head of the Mosquito. ]

The Mosquito will be our first choice. As she leaps off from her lightbark, the cast chrysalis skin of her early life beneath the waters, andsails away in the sunlight, her velvety wings fringed with silken hairs, and her neatly bodiced trim figure (though her nose is rather salient, considering that it is half as long as her entire body), present abeauty and grace of form and movement quite unsurpassed by her dipterousallies. She draws near and softly alights upon the hand of the charmedbeholder, subdues her trumpeting notes, folds her wings noiselessly uponher back, daintily sets down one foot after the other, and with aneagerness chastened by the most refined delicacy for the feelings of hervictim, and with the air of Velpeau redivivus, drives through crushedand bleeding capillaries, shrinking nerves and injured tissues, amany-bladed lancet of marvellous fineness, of wonderful complexity andfitness. While engorging herself with our blood, we will examine underthe microscope the mosquito's mouth. The head (Fig. 61) is rounded, withthe two eyes occupying a large part of the surface, and nearly meetingon the top of the head. Out of the forehead, so to speak, grow the long, delicate, hairy antennm (_a_), and just below arises the long beak whichconsists of the bristle-like maxillæ (_mx_, with their palpi, _mp_) andmandibles (_m_), and the single hair-like labrum, these fivebristle-like organs being laid in the hollowed labium (_l_). Thus massedinto a single awl-like beak, the mosquito, without any apparent effort, thrusts them all except the labium into the flesh. Her hind body may beseen tilling with the red blood, until it cries quits, and the insectwithdraws its sting and flies sluggishly away. In a moment the woundedparts itch slightly, though a very robust person may not notice theirritation, or a more delicate individual if asleep; though if weakenedby disease, or if stung in a highly vascular and sensitive part, such asthe eyelid, the bite becomes really a serious matter. Multiply themosquito a thousand fold, and one flees their attacks and avoids theirhaunts as he would a nest of hornets. Early in spring the larva (Fig. 62, A) of the mosquito may be found in pools and ditches. It remains atthe bottom feeding upon decaying matter (thus acting as a scavenger, andin this state doing great benefit in clearing swamps of miasms), untilit rises to the surface for air, which it inhales through a singlerespiratory tube (_c_) situated near the tail. When about to transforminto the pupa state, it contracts and enlarges anteriorly near themiddle, the larval skin is thrown off, and the insect appears in quite adifferent form (Fig. 62, a). The head and thorax are massed together, the rudiments of the mouth parts and of the wings and legs being foldedupon the breast, while there are two breathing tubes (_d_) situated uponthe back instead of the tail, which ends in two broad paddles (_a_); sothat it comes to the surface, head foremost instead of tail first, aposition according better with its increased age and experience in pondlife. In a few days the pupa skin is cast; the insect, availing itselfof its old habiliments as a raft upon which to float while its body isdrying, grows lighter, and its wings expand for its marriage flight. Themales are beautiful, both physically and morally, as they do not bite;their manners are more retiring than those of their stronger mindedpartners, as they rarely enter our dwellings, and live unnoticed in thewoods. They may be easily distinguished from the females by their longmaxillary palpi, and their thick, bushy, feathered antennæ. The femalelays her elongated, oval eggs in a boat-shaped mass, which floats on thewater. A mosquito lives three or four weeks in the water before changingto the adult or winged stage. How many days they live in the latterstate we do not know. 

[Illustration: 62. Larva and Pupa of the Mosquito. ]

Our readers will understand, then, that all flies, like our mosquito forexample, grow while in the larva and pupa state, _and after they acquirewings do not grow_, so that the small midges are not young mosquitoes, but the adult winged forms of an entirely different species and genus offly; and the myriads of small flies, commonly supposed to be the youngof larger flies, are adult forms belonging to different species ofdifferent genera, and perhaps of different families of the suborder ofDiptera. The typical species of the genus Culex, to which the mosquitobelongs, is Culex pipiens, described by Linnæus, and there are alreadyover thirty North American species of this genus described in variousworks. Few insects live in the sea, but along the coast of New Englanda small, slender white larva (Fig. 63a, magnified, and head greatlyenlarged; Fig. 64, pupa and fore foot of larva, showing the hooks), whose body is no thicker than a knitting needle, lives between tides, and has even been dredged at a depth of over a hundred feet, whichtransforms into a yellow mosquito-like fly (Fig. 65, with head of thefemale, magnified) which swarms in summer in immense numbers. I havecalled it provisionally Chironomus oceanicus, or Ocean gnat. The larvæof other species have been found by Mr. S. I. Smith living at greatdepths in our Northern lakes. These kinds of gnats are usually seenearly in spring hovering in swarms in mid air. 

[Illustration: 65. Ocean Gnat. ]

[Illustration: 63. Larva of Ocean Gnat. ]

[Illustration: 64. Pupa of Ocean Gnat. ]

The strange fact has been discovered by Grimm, a Russian naturalist, that the pupa of a feathered gnat is capable of laying eggs whichproduce young during the summer time. Previous to this it had beendiscovered that a larva of a gnat (Fig. 66 _a_, eggs from which theyoung are produced) which lives under the bark of trees in Europe, alsoproduced young born alive. 

The Hessian fly (Fig. 67, _a_, larva; _b_ pupa; _c_, stalk of wheatinjured by larvæ) and Wheat midge, which are allied to the mosquito, arebriefly referred to in the calendar, so that we pass over these toconsider another pest of our forests and prairies. 

[Illustration: 66. Viviparous gall larva. ]

[Illustration: 67. Hessian Fly and its Young. ]

The Black fly is even a more formidable pest than the mosquito. In thenorthern, subarctic regions, it opposes a barrier against travel. TheLabrador fisherman spends his summer on the sea shore, scarcely daringto penetrate the interior on account of the swarms of these flies. During a summer residence on this coast, we sailed up the Esquimauxriver for six or eight miles, spending a few hours at a house situatedon the bank. The day was warm and but little wind blowing, and theswarms of black flies were absolutely terrific. In vain we franticallywaved our net among them, allured by some rare moth; after making a fewdesperate charges in the face of the thronging pests, we had to retireto the house, where the windows actually swarmed with them; but herethey would fly in our faces, crawl under one's clothes, where they evenremain and bite in the night. The children in the house were sickly andworn by their unceasing torments; and the shaggy Newfoundland dogs whosethick coats would seem to be proof against their bites ran from theirshelter beneath the bench and dashed into the river, their only retreat. In cloudy weather, unlike the mosquito, the black fly disappears, onlyflying when the sun shines. The bite of the black fly is often severe, the creature leaving a large clot of blood to mark the scene of itssurgical triumphs. Prof. E. T. Cox, State Geologist of Indiana, has sentus specimens of a much larger fly, which Baron Osten Sacken refers tothis genus, which is called on the prairies, where it is said to bitehorses to death, the Buffalo Gnat. Westwood states that an allied fly(Rhagio Columbaschensis) is one of the greatest scourges of man andbeast in Hungary, where it has been known to kill cattle. 

[Illustration: 68. Black fly. ]

[Illustration: 69. Black Fly Larva. ]

The Simulium molestum (Fig. 68, enlarged), as the black fly is called, lives during the larva state in the water. The larva of a Labradorspecies (Fig. 69, enlarged) which we found, is about a quarter of aninch long, and of the appearance here indicated. The pupa is alsoaquatic, having long respiratory filaments attached to each side of thefront of the thorax. According to Westwood, "the posterior part of itsbody is enclosed in a semioval membranous cocoon, which is at firstformed by the larva, the anterior part of which is eaten away beforechanging to a pupa, so as to be open in front. The imago is producedbeneath the surface of the water, its fine silky covering serving torepel the action of the water. "

[Illustration: 70. Mycetobia. ]

Multitudes of a long, slender, white worm may often be found living inthe dirt, and sour sap running from wounds in the elm tree. Two summersago we discovered some of these larvæ, and on rearing them found thatthey were a species of Mycetobia (Fig. 70; _a_, larva; _b_, pupa). Thelarva is remarkable for having the abdominal segments divided into twoportions, the hinder much smaller than the anterior division. Its wholelength is a little over a third of an inch. The pupæ were found stickingout in considerable numbers from the tree, being anchored by the littlespines at the tail. The head is square, ending in two horns, and thebody is straight and covered with spines, especially towards the end ofthe tail. They were a fifth of an inch in length. The last of June theflies appeared, somewhat resembling gnats, and about a line long. Theworms continued to infest the tree for six weeks, the flies remainingeither upon or near it. 

[Illustration: 71. Mouth Parts of Tabanus. ]

We now come to that terror of our equine friends, the Horse fly, Gad, orBreeze fly. In its larval state, some species live in water, and in dampplaces under stones and pieces of wood, and others in the earth awayfrom water, where they feed on animal, and, probably, on decayingmatter. Mr. B. D. Walsh found an aquatic larva of this genus, which, within a short time, devoured eleven water snails. Thus at this stage ofexistence, this fly, often so destructive, even at times killing ourhorses, is beneficial. During the hotter parts of summer, and when thesun is shining brightly, thousands of these Horse flies appear on ourmarshes and inland prairies. There are many different kinds, over onehundred species of the genus Tabanus alone, living in North America. Ourmost common species is the "Green head, " or Tabanus lineola. When aboutto bite, it settles quietly down upon the hand, face or foot, it mattersnot which, and thrusts its formidable lancet-like jaws deep into theflesh. Its bite is very painful, as we can testify from personalexperience. We were told during the last summer that a horse, whichstood fastened to a tree in a field near the marshes at Rowley, Mass. , was bitten to death by these Green heads; and it is known that horsesand cattle are occasionally killed by their repeated harassing bites. Incloudy weather they do not fly, and they perish on the cool frostynights of September. The Timb, or Tsetze fly, is a species of this groupof flies, and while it does not attack man, plagues to death, and issaid to poison by its bite, the cattle in certain districts of theinterior of Africa, thus almost barring out explorers. On comparing themouth-parts of the Horse fly (Fig. 71, mouth of T. Lineola), we have allthe parts seen in the mosquito, but greatly modified. Like the mosquito, the females alone bite, the male Horse fly being harmless, andfrequenting flowers, living upon their sweets. The labrum (_lb_), mandibles (_m_) and maxillæ (_mx_), are short, stiff and lancet-like, and the maxillary palpi (_mp_; _a_, the five terminal joints of theantennæ) are large, stout, and two-jointed. While the jaws (both maxillæand mandibles) are thrust into the flesh, the tongue (_l_) spreadsaround the tube thus formed by the lancets, and pumps up the bloodflowing from the wound, by aid of the sucking stomach, or crop, being asac appended to the throat. Other Gad flies, but much smaller, though asannoying to us in woods and fields, are the species of Golden eyedflies, Chrysops, which fly and buzz interminably about our ears, oftentaking a sudden nip. They plague cattle, settling upon them and drawingtheir blood at their leisure. 

[Illustration: 72. Carpet Fly. ]

[Illustration: 73. Carpet Worm. ]

We turn to a comparatively unknown insect, which has occasionallyexcited some distrust in the minds of housekeepers. It is the carpetfly, Scenopinus pallipes (Fig. 72), which, in the larva state, is foundunder carpets, on which it is said to feed. The worm (Fig. 73) has along, white, cylindrical body, divided into twelve segments, exclusiveof the head, while the first eight abdominal segments are divided by atransverse suture, so that there appear to be seventeen abdominalsegments, the sutures appearing too distinct in the cut. Mr. F. G. Sanborn has reared the fly, here figured, from the worm. The larva alsolives in rotten wood; it is too scarce ever to prove very destructive inhouses. Either this or a similar fly was once found, we are told by ascientific friend, in great numbers in a "rat" used in dressing a younglady's hair; the worms were living upon the hair stuffing. 

One of the most puzzling objects to the collector of shells or insects, is the almost spherical larva of Microdon globosus (Fig. 74). It isflattened and smooth beneath and seems to adhere to the under side ofstones, where it might be mistaken for a snail. 

The Syrphus fly, or Aphis eater, deserves more than the passing noticewhich we bestow upon it. The maggot (Fig. 75, in the act of devouring anAphis) is to be sought for established in a group of plant lice (Aphis), which it seizes by means of the long extensible front part of the body. The adult fly (Fig. 76) is gayly spotted and banded with yellow, resembling closely a wasp. It frequents flowers. 

[Illustration: 74. Microdon. ]

[Illustration: 75. Syrphus Larva. ] 76. Syrphus Fly. ]

[Illustration: 77. Larva of Rat-tailed Fly. 78. Rat-tailed Fly and itsPupa. ]

The singular rat-tailed pupa-case of Eristalis (Fig. 77) lives in water, and when in want of air, protrudes its long respiratory tube out intothe air. We present the figure of an allied fly, Merodon Bardus (Fig. 78; _a_, puparium, natural size). We will not describe at length thefly, as the admirable drawings of Mr. Emerton cannot fail to render iteasily recognizable. The larva is much like the puparium or pupa case, here figured, which closely resembles that of Eristalis, in possessingalong respiratory filament, showing that the maggot undoubtedly lives inthe water, and when desirous of breathing, protrudes the tube out of thewater, thus drawing in air enough to fill its internal respiratory tubes(tracheæ). The Merodon Narcissa probably lives in the soil, or in rottenwood, as the pupa-case has no respiratory tube, having instead a veryshort, sessile, truncated tube, scarcely as long as it is thick. Thecase itself is cylindrical, and rounded alike at each end. 

[Illustration: 79. Human Bot Worm. ]

We now come to the Bot flies, which are among the most extraordinary, intheir habits, of all insects. The history of the Bot flies is in briefthus. The adult two-winged fly lays its eggs on the exterior of theanimal to be infested. They are conveyed into the interior of the host, where they hatch, and the worm or maggot lives by sucking in thepurulent matter, caused by the irritation set up by its presence in itshost; or else the worm itself, after hatching, bores under the skin. When fully grown, it quits the body and finishes its transformations tothe fly-state under ground. Many quadrupeds, from mice, squirrels, andrabbits, up to the ox, horse, and even the rhinoceros, suffer from theirattacks, while man himself is not exempt. The body of the adult fly isstout and hairy, and it is easily recognized by having the opening ofthe mouth very small, the mouth-parts being very rudimentary. The larvæare, in general, thick, fleshy, footless grubs, consisting of elevensegments, exclusive of the head, which are covered with rows of spinesand tubercles, by which they move about within the body, thus irritatingthe animals in which they take up their abode. The breathing pores(stigmata) open in a scaly plate at the posterior end of the body. Themouth-parts (mandibles, etc. ) of the subcutaneous larvæ consist offleshy tubercles, while in those species which live in the stomachs andfrontal sinuses of their host, they are armed with horny hooks. 

[Illustration: 80. Horse Bot Fly. ]

The larvæ attain their full size after moulting twice. Just beforeassuming the pupa state, the maggot leaves its peculiar dwelling place, descends into the ground and there becomes a pupa, though retaining itslarval skin, which serves as a protection to it, whence it is called a"puparium. "

Several well-authenticated instances are on record of a species of botfly inhabiting the body of man, in Central and South America, producingpainful tumors under the skin of the arm, legs and abdomen. It is stillunder dispute whether this human bot fly is a true or accidentalparasite, the more probable opinion being that its proper host is themonkey or dog. In Cayenne, this revolting grub is called the Ver macaque(Fig. 79); in Para, Ura; in Costa Rica, Torcel; and in New Granada, Gusano peludo, or Nuche. The Dermatobia noxialis, supposed to be the Vermoyocuil of the inhabitants of Mexico and New Granada, lives beneath theskin of the dog. 

[Illustration: 81. Bot Fly of Ox, and Larva. ]

[Illustration: 82. Sheep Bot. ]

[Illustration: 83. Skin Bot Fly. ]

The Bot fly of the horse, (Gastrophilus equi, Fig. 80 and larva), ispale yellowish, spotted with red, with short, grayish, yellow hairs, andthe wings are banded with reddish. She lays her eggs upon the knees ofthe horse. They are conveyed into the stomach, where the larva livesfrom May until October, and when full grown are found hanging by theirmouth hooks on the edge of the rectum of the horse, whence they arecarried out in the excrement. The pupa state lasts for thirty or fortydays, and the perfect fly appears the next season, from June untilOctober. 

The Bot fly of the ox (Hypoderma bovis, Fig. 81, and larva), is blackand densely hairy, and the thorax is banded with yellow and white. Thelarva is found during the month of May, and also in summer, living intumors on the backs of cattle. When fully grown, which is generally inJuly, they make their way out and fall to the ground, and live in thepupa-case from twenty-six to thirty days, the fly appearing from Mayuntil September. It is found all over the world. The Oestrus ovis, orsheep Bot fly (Fig. 82, larva), is of a dirty ash color. The abdomen ismarbled with yellowish and white flecks, and is hairy at the end. Thisspecies of Bot fly is larviparous, i. E. , the eggs are hatched within thebody of the mother, the larvæ being produced alive. M. F. Brauer, ofVienna, the author of the most thorough work we have on these flies, tells me that he knows of but one other Bot fly (a species ofCephanomyia) which produces living larvæ instead of eggs. The eggs ofcertain other species of Bot flies do not hatch until three or four daysafter they are laid. The larvæ of the sheep Bot fly live, during April, May and June, in the frontal sinus of the sheep, and also in the nasalcavity, whence they fall to the ground when fully grown. In twenty-fourhours they change to pupæ, and the flies appear during the summer. 

We also figure the Cuterebra buccata (Fig. 83; _a_, side view, ) whichresembles in the larval state the ox Bot fly. Its habits are not known, though the young of other species infest the opossum, squirrel, hare, etc. , living in subcutaneous tumors. 

[Illustration: The banded Lithacodes. ]

CHAPTER VII. 

THE HOUSE FLY AND ITS ALLIES. 

[Illustration: 84. Mouth-parts of the House fly. ]

The common House fly, Musca domestica, scarcely needs an introduction toany one of our readers, and its countenance is so well known that weneed not present a portrait here. But a study of the proboscis of thefly reveals a wonderful adaptability of the mouth-parts of this insectto their uses. We have already noticed the most perfect condition ofthese parts as seen in the horse fly. In the proboscis of the house flythe hard parts are obsolete, and instead we have a fleshy tongue likeorgan (Fig. 84), bent up beneath the head when at rest. The maxillæ areminute, their palpi (_mp_) being single-jointed, and the mandibles (_m_)are comparatively useless, being very short and small, compared with thelancet-like jaws of the mosquito or horse fly. But the structure of thetongue itself (labium, l) is most curious. When the fly settles upon alump of sugar or other sweet object, it unbends its tongue, extends it, and the broad knob-like end divides into two broad, flat, muscularleaves (_l_), which thus present a sucker-like surface, with which thefly laps up liquid sweets. These two leaves are supported upon aframework of tracheal tubes. In the cut given above, Mr. Emerton hasfaithfully represented these modified trachæ, which end in hairsprojecting externally. Thus the inside of this broad fleshy expansionis rough like a rasp, and as Newport states, "is easily employed by theinsect in scraping or tearing delicate surfaces. It is by means of thiscurious structure that the busy house fly occasions much mischief to thecovers of our books, by scraping off the albuminous polish, and leavingtracings of its depredations in the soiled and spotted appearance whichit occasions on them. It is by means of these also that it teases us inthe heat of summer, when it alights on the hand or face to sip theperspiration as it exudes from, and is condensed upon, the skin. "

[Illustration: 85. Larva; _a_, Pupa-case of House fly. ]

[Illustration: 86. Larva of Flesh fly. ]

Every one notices that house flies are most abundant around barns inAugust and September, and it is in the ordure of stables that the earlystages of this insect are passed. No one has traced the transformationsof this fly in our country, but we copy from Bouché's work on thetransformations of insects, the rather rude figures of the larva (Fig. 85), and pupa-case (_a_) of the Musca domestica of Europe, which issupposed to be our species. Bouché states that the larva is cylindrical, rounded posteriorly, smooth and shining, fleshy, and yellowish white, and four lines long. The pupa-case, or puparium, is dark reddish-brown, and three lines in length. It remains in the pupa state from eight tofourteen days. In Europe it is preyed upon by minute ichneumon flies(Chalcids). The flesh fly, Musca Cæsar, or the Blue-bottle fly, feedsupon decaying animal matter. Its larva (Fig. 86) is long, cylindrical, the head being pointed, and the body conical, the posterior end beingsquarely docked. The larva of a Sargus-like form which feeds on offal, transforms into a flattened pupa-case (Fig. 87), provided with long, scattered hairs. The House fly disappears in autumn, at the approach ofcold weather, though a few individuals pass through the winter, hibernating in houses, and when the rooms are heated may often be seenflying on the windows. Other species fly early in March, on warm days, having hibernated under leaves, and the bark of trees, moss, etc. Anallied species, the M. Vomitoria, is the Meat fly. Closely allied arethe parasitic species of Tachina, which live within the bodies ofcaterpillars and other insects, and are among the most beneficial ofinsects, as they prey on thousands of injurious caterpillars. Anotherfly of this Muscid group, the Idia Bigoti, according to Coquerel andMondiere, produces in the natives of Senegal, hard, red, fluctuatingtumors, in which the larva resides. 

[Illustration: 87. Larva of a Sargus-like fly. ]

Many of the smaller Muscids mine leaves, running galleries within theleaf, or burrowing in seeds or under the bark of plants. We have oftennoticed blister-like swellings on the bark of the willow, which areoccasioned by a cylindrical, short, fleshy larva (Fig. 88_a_, muchenlarged), about a line in length, which changes to a pupa within theold larval skin, assuming the form here represented (Fig. 88_b_), andabout the last of June changes to a small black fly (Fig. 88), whichBaron Osten Sacken refers doubtfully to the genus Lonchæa. 

[Illustration: 86. Willow Blister fly. ]

The Apple midge frequently does great mischief to apples after they aregathered. Mr. F. G. Sanborn states that nine-tenths of the apple crop inWrentham, Mass. , were destroyed by a fly supposed to be the Molobrusmali, or Apple midge, described by Dr. Fitch. "The eggs were supposed tohave been laid in fresh apples, in the holes made by the Coddling moth(Carpocapsa pomonella), whence the larvæ penetrated into all parts ofthe apple, working small cylindrical burrows about one-sixteenth of aninch in diameter. " Mr. W. C. Fish has also sent me, from Sandwich, Mass. , specimens of another kind of apple worm, which he writes has beenvery common in Barnstable county. "It attacks mostly the earliervarieties, seeming to have a particular fondness for the old fashionedSummer, or High-top Sweet. The larvæ (Fig. 89 _a_) enter the fruitusually where it has been bored by the Apple worm (Carpocapsa), notuncommonly through the crescent-like puncture of the curculio, andsometimes through the calyx, when it has not been troubled by otherinsects. Many of them arrive at maturity in August, and the fly soonappears, successive generations of the maggots following until coldweather. I have frequently found the pupæ in the bottom of barrels in acellar in the winter, and the flies appear in the spring. In the earlyapples, the larvæ work about in every direction. If there be several inan apple, they make it unfit for use. Apples that appear perfectly soundwhen taken from the tree, will sometimes, if kept, be all alive withthem in a few weeks. " Baron Osten Sacken informs me that it is aDrosophila, "the species of which live in putrescent vegetable matter, especially fruits. "

[Illustration: 89. Apple Worm and its Larva. ]

[Illustration: 90. Parent of the Cheese Maggot. ]

[Illustration: 91. Pupa case of Wine-fly. ]

An allied fly is the parent of the cheese maggot. The fly itself(Piophila casei, Fig. 90) is black, with metallic green reflections, andthe legs are dark and paler at the knee-joints, the middle and hind pairof tarsi being dark honey yellow. The Wine fly is also a Piophila, andlives the life of a perpetual toper in old wine casks, and partiallyemptied beer, cider and wine bottles, where, with its pupa-case (Fig. 91), it may be found floating dead in its favorite beverage. 

[Illustration: 92. Bird Tick. ]

We now come to the more degraded forms of flies which live parasiticallyon various animals. We figure, from a specimen in the Museum of thePeabody Academy of Science, the Bird tick (Ornithomyia, Fig. 92), whichlives upon the Great Horned Owl. Its body is much flattened, adapted forits life under the feathers, where it gorges itself with the blood ofits host. 

[Illustration: 93. The Horse Tick. ]

Here belongs also the Horse tick (Hippobosca equina, Fig. 93). It isabout the size of the house fly, being black, with yellow spots on thethorax. Verrill[4] says that "it attacks by preference those parts wherethe hair is thinnest and the skin softest, especially under the bellyand between the hind legs. Its bite causes severe pain, and willirritate the gentlest horses, often rendering them almost unmanageable, and causing them to kick dangerously. When found, they cling so firmlyas to be removed with some difficulty, and they are so tough as not tobe readily crushed. If one escapes when captured, it will instantlyreturn to the horse, or, perchance, to the head of its captor, where itis an undesirable guest. Another species sometimes infests the ox. "

[Illustration: 94. Sheep Tick. ]

[Illustration: 95. Bat Tick. ]

In the wingless Sheep tick (Melophagus ovinus, Fig. 94, with thepupa-case on the left), the body is wingless and very hairy, and theproboscis is very long. The young are developed within the body of theparent, until they attain the pupa state, when she deposits the pupacase, which is nearly half as large as her abdomen. Other genera areparasitic on bats; among them are the singular spider-like Bat ticks(Nycteribia, Fig. 95), which have small bodies and enormous legs, andare either blind, or provided with four simple eyes. They are of smallsize, being only a line or two in length. Such degraded forms of Dipterahave a remarkable resemblance to the spiders, mites, ticks, etc. Thereader should compare the Nycteribia with the young six-footed moosetick figured farther on. Another spider-like fly is the Chionea valga(Fig. 96; and 97, larva of the European species), which is a degradedTipula, The latter genus standing near the head of the Diptera. TheChionea, according to Harris, lives in its early, stages in the groundlike many other gnats, and is found early in the spring, sometimescrawling over the snow. We have also figured and mentioned previously(page 41) the Bee louse, Braula, another wingless spider-like fly. 

[Illustration: 96. Spider fly. ]

[Illustration: 97. Larva of Spider fly. ]

The Flea is also a wingless fly, and is probably, as has been suggestedby an eminent entomologist, as Baron Osten Sacken informs us, a degradedgenus of the family to which Mycetobia belongs. Its transformations arevery unlike those of the fly ticks, and agree closely with the earlystages of Mycetophila, one of the Tipulid family. In its adult conditionthe flea combines the characters of the Diptera, with certain featuresof the grasshoppers and cockroaches, and the bugs. The body of the flea(Fig. 98, greatly magnified; _a_, antennæ; _b_, maxillæ, and theirpalpi, _c_; _d_, mandibles; the latter, with the labium, which is notshown in the figure, forming the acute beak) is much compressed, andthere are minute wing-pads, instead of wings, present in some species. 

[Illustration: 98. Flea, magnified. ]

[Illustration: 99. Larva of Flea. ]

Dr. G. A. Perkins, of Salem, has succeeded in rearing in considerablenumbers from the eggs, the larvæ of this flea. The larvæ (Fig. 99, muchenlarged; _a_, antenna; _b_, the terminal segments of the abdomen), whenhatched, are half a line in length. The body is long, cylindrical, andpure white, with thirteen segments exclusive of the head, and providedwith rather long hairs. It is very active in its movements, and lives onblood clots, remaining on unswept floors of out-houses, or in the strawor bed of the animals they infest. In six days after the eggs are laidthe larvæ appear, and in a few days after leaving the egg they mature, spin a rude cocoon, and change to pupæ, and the perfect insects appearin about ten days. A good authority states that the human flea does notexist in America. We never saw a specimen in this country. 

A practical point is how to rid dogs of fleas. As a preventive measure, we would suggest the frequent sweeping and cleansing of the floors oftheir kennels, and renewing the straw or chips composing theirbeds, --chips being the best material for them to sleep upon. Fleaafflicted dogs should be washed every few days in strong soapsuds, orweak tobacco or petroleum water. 

A writer in "Science-Gossip" recommends the "use of the Persian InsectDestroyer, one package of which suffices for a good sized dog. Thepowder should be well rubbed in all over the skin, or the dog, if small, can be put into a bag previously dusted with the powder; in either casethe dog should be washed soon after. "

[Illustration: 100. Chique. ]

One of the most serious insect torments of the tropics of America is theSarcopsylla penetrans, called by the natives the Jigger, Chigoe, Bicho, Chique, or Pique (Fig. 100, enlarged; a, gravid female, natural size). The female, during the dry season, bores into the feet of the natives, the operation requiring but a quarter of an hour, usually penetratingunder the nails, and lives there until her body becomes distended witheggs, the hind-body swelling out to the size of a pea; her presenceoften causes distressing sores. The Chigoe lays about sixty eggs, depositing them in a sort of sac on each side of the external opening ofthe oviduct. The young develop and feed upon the swollen body of theparent flea until they mature, when they leave the body of their hostand escape to the ground. The best preventive is cleanliness and theconstant wearing of shoes or slippers when in the house, and of bootswhen out of doors. 

[Illustration: The Willow Gall Fly. ]

CHAPTER VIII. 

THE BORERS OF OUR SHADE TREES. 

In no way can the good taste and public spirit of our citizens be bettershown than in the planting of shade trees. Regarded simply from acommercial point of view one cannot make a more paying investment thansetting out an oak, elm, maple or other shade tree about his premises. To a second generation it becomes a precious heirloom, and the planteris duly held in remembrance for those finer qualities of heart and head, and the wise forethought which prompted a deed simple and natural, but adeed too often undone. What an increased value does a fine avenue ofshade trees give to real estate in a city? And in the country the singlestately elm rising gracefully and benignantly over the wayside cottage, year after year like a guardian angel sending down its blessings ofshade, moisture and coolness in times of drought, and shelter from thepitiless storm, recalls the tenderest associations of generation aftergeneration that go from the old homestead. 

Occasionally the tree, or a number of them, sicken and die, or lingerout a miserable existence, and we naturally after failing to ascribe thecause to bad soil, want of moisture or adverse atmospheric agencies, conclude that the tree is infested with insects, especially if the barkin certain places seems diseased. Often the disease is in streetslighted by gas, attributed to the leakage of the gas. Such a case hascome up recently at Morristown, New Jersey. An elm was killed by the Elmborer (Compsidea tridentata), and the owner was on the point of suingthe Gas Company for the loss of the tree from the supposed leakage of agas pipe. While the matter was in dispute, a gentleman of that city tookthe pains to peel off a piece of the bark and found, as he wrote me, "great numbers of the larvæ of this beetle in the bark and between thebark and the wood, while the latter is 'tattooed' with sinuous groovesin every direction and the tree is completely girdled by them in someplaces. There are three different sizes of the larvæ, evidently one, twoand three years old, or more properly six, eighteen and thirty monthsold. " The tree had to be cut down. 

Dr. Harris, in his "Treatise on Injurious Insects, " gives an account ofthe ravages of this insect, which we quote: "On the 19th of June, 1846, Theophilus Parsons, Esq. , sent me some fragments of bark and insectswhich were taken by Mr. J. Richardson from the decaying elms on BostonCommon, and among the insects I recognized a pair of these beetles in aliving state. The trees were found to have suffered terribly from theravages of these insects. Several of them had already been cut down, aspast recovery; others were in a dying state, and nearly all of them weremore or less affected with disease or premature decay. Their bark wasperforated, to the height of thirty feet from the ground, with numerousholes, through which insects had escaped; and large pieces had become soloose, by the undermining of the grubs, as to yield to slight efforts, and come off in flakes. The inner bark was filled with burrows of thegrubs, great numbers of which, in various stages of growth, togetherwith some in the pupa state, were found therein; and even the surface ofthe wood, in many cases, was furrowed with their irregular tracks. Veryrarely did they seem to have penetrated far into the wood itself; buttheir operations were mostly confined to the inner layers of the bark, which thereby became loosened from the wood beneath. The grubs rarelyexceed three-quarters of an inch in length. They have no feet, and theyresemble the larvæ of other species of Saperda, except in being rathermore flattened. They appear to complete their transformations in thethird year of their existence. 

"The beetles probably leave their holes in the bark during the month ofJune and in the beginning of July, for, in the course of thirty years, Ihave repeatedly taken them at various dates, from the fifth of June tothe tenth of July. It is evident, from the nature and extent of theirdepredations, that these insects have alarmingly hastened the decay ofthe elm trees on Boston Mall and Common, and that they now threatentheir entire destruction. Other causes, however, have probablycontributed to the same end. It will be remembered that these treeshave greatly suffered, in past times, from the ravages of canker-worms. Moreover, the impenetrable state of the surface soil, the exhaustedcondition of the subsoil, and the deprivation of all benefit from thedecomposition of accumulated leaves, which, in a state of nature, thetrees would have enjoyed, but which a regard for neatness hasindustriously removed, have doubtless had no small influence indiminishing the vigor of the trees, and thus made them fallunresistingly a prey to insect devourers. The plan of this workprecludes a more full consideration of these and other topics connectedwith the growth and decay of these trees; and I can only add, that itmay be prudent to cut down and burn all that are much infested by theborers. "

[Illustration: 101. Elm Tree Beetle. ]

The Three-toothed Compsidea (Fig. 101), is a rather flat-bodied, darkbrown beetle, with a rusty red curved line behind the eyes, two stripeson the thorax, and a three-toothed stripe on the outer edge of each wingcover. It is about one-half an inch in length. 

[Illustration: 102. Elm Tree Borer. ]

The larva (Fig. 102) is white, subcylindrical, a little flattened, withthe lateral fold of the body rather prominent; the end of the body isflattened, obtuse, and nearly as wide at the end as at the firstabdominal ring. The head is one-half as wide as the prothoracic ring, being rather large. The prothoracic ring, or segment just behind thehead, is transversely oblong, being twice as broad as long; there is apale dorsal corneous transversely oblong shield, being about two-thirdsas long as wide, and nearly as long as the four succeeding segments;this plate is smooth, except on the posterior half, which is rough, withthe front edge irregular and not extending far down the sides. Finehairs arise from the front edge and side of the plate, and similar hairsare scattered over the body and especially around the end. On the upperside of each segment is a transversely oblong ovate roughened area, withthe front edge slightly convex, and the hinder slightly arcuate. On theunder side of each segment are similar rough horny plates, but arcuatein front, with the hinder edge straight. 

It differs from the larva of the Linden tree borer (Saperda vestita) inthe body being shorter, broader, more hairy, with the tip of the abdomenflatter and more hairy. The prothoracic segment is broader and flatter, and the rough portion of the dorsal plates is larger and lesstranversely ovate. The structure of the head shows that its genericdistinctness from Saperda is well founded, as the head is smaller andflatter, the clypeus being twice as large, and the labrum broad andshort, while in S. Vestita it is longer than broad. The mandibles aremuch longer and slenderer, and the antennæ are much smaller than in S. Vestita. 

[Illustration: 103. Linden Tree Beetle. ]

[Illustration: 104. Linden Tree Borer. ]

The Linden tree borer (Fig. 103) is a greenish snuff-yellow beetle, withsix black spots near the middle of the back; and it is abouteight-tenths of an inch in length, though often smaller. The beetles, according to Dr. Paul Swift, as quoted by Dr. Harris, were found (inPhiladelphia) upon the small branches and leaves on the 28th day of May, and it is said that they come out as early as the first of the month, and continue to make their way through the back of the trunk and largebranches during the whole of the warm season. They immediately fly intothe top of the tree, and there feed upon the epidermis of the tendertwigs, and the petioles of the leaves, often wholly denuding the latter, and causing the leaves to fall. They deposit their eggs, two or three ina place, upon the trunk or branches especially about the forks, makingslight incisions or punctures for their reception with their strongjaws. As many as ninety eggs have been taken from a single beetle. Thegrubs (Fig. 104, _e_; _a_, enlarged view of the head seen from above;_b_, the under view of the same: _c_, side view, and _d_, two rings ofthe body enlarged), hatched from these eggs, undermine the bark to theextent of six or eight inches, in sinuous channels, or penetrate thesolid wood an equal distance. It is supposed that three years arerequired to mature the insect. Various expedients have been tried toarrest their course, but without effect. A stream, thrown into the topsof trees from the hydrant, is often used with good success to dislodgeother insects; but the borer-beetles, when thus disturbed, take wing andhover over the trees till all is quiet, and then alight and go to workagain. The trunks and branches of some of the trees have been washedover with various preparations without benefit. Boring the trunk nearthe ground and putting in sulphur and other drugs, and plugging, havebeen tried with as little effect. 

[Illustration: 105. Poplar Tree Borer. ]

The city of Philadelphia has suffered grievously from this borer. 

[Illustration: 106. Broad-necked Prionus. ]

Dr. Swift remarks, in 1844, that "the trees in Washington andIndependence Squares were first observed to have been attacked aboutseven years ago. Within two years it has been found necessary to cutdown forty-seven European lindens in the former square alone, wherethere now remain only a few American lindens, and these a good dealeaten. " In New England this beetle should be looked for during the firsthalf of June. 

[Illustration: 107. Larva of the Plain Saperda. ]

The Poplar tree is infested by an other species of Saperda (S. Calcarata). This is a much larger beetle than those above mentioned, being an inch or a little more in length. It is grey, irregularlystriped, with ochre, and the wing-covers end in a sharp point. The grub(Fig. 105 _a_; _b_, top view of the head; _e_, under side) is about twoinches long and whitish yellow. It has, with that of the Broad-neckedPrionus (P. Laticollis of Drury, Fig. 106, adult and pupa), as Harrisstates, "almost entirely destroyed the Lombardy poplar in this vicinity"(Boston). It bores in the trunks, and the beetle flies by night inAugust and September. We also figure the larva of another borer (Fig. 107 _c_; _a_, top view of the head; _b_, under side; _e_, dorsal view ofan abdominal segment; _d_, end of the body, showing its peculiar form), the Saperda inornata of Say, the beetle of which is black, with ash grayhairs, and without spines on the wing-covers. It is much smaller thanany of the foregoing species, being nine-twentieths of an inch inlength. Its habits are not known. We also figure the Locust and Hickoryborer (Fig. 108; _a_, larva; _b_, pupa), which has swept off the locusttree from New England. The beautiful yellow banded beetles are veryabundant on the flowers of the golden rod in September. 

[Illustration: 108. Locust Borer. ]

FOOTNOTES:

[Footnote 4: The External and Internal Parasites of Man and DomesticAnimals. By Prof. A. E. Verrill, 1870. We are indebted to the author forthe use of this and the figures of the Bot fly of the horse, the turkey, duck and hog louse, the Cattle tick, the itch insect and mange insect ofthe horse. ]

CHAPTER IX. 

CERTAIN PARASITIC INSECTS. 

The subject of our discourse is not only a disagreeable but too often apainful one. Not only is the mere mention of the creature's name ofwhich we are to speak tabooed and avoided by the refined and polite, butthe creature itself has become extinct and banished from the society ofthe good and respectable. Indeed under such happy auspices do a largeproportion of the civilized world now live that their knowledge of thehabits and form of a louse may be represented by a blank. Not so withsome of their great-great-grandfathers and grandmothers, if history, sacred and profane, poetry, [5] and the annals of literature testifyaright; for it is comparatively a recent fact in history that the lousehas awakened to find himself an outcast and an alien. Among savagenations of all climes, some of which have been dignified with the apt, though high sounding name of Phthiriophagi, and among the Chinese andother semi-civilized peoples, these lords of the soil still flourishwith a luxuriance and rankness of growth that never diminishes, so thatwe may say without exaggeration that certain mental traits and fleshlyappetites induced by their consumption as an article of food may havebeen created, while a separate niche in our anthropological museums isreserved for the instruments of warfare, both offensive and defensive, used by their phthiriophagous hunters. Then have we not in the verycentres of civilization the poor and degraded, which are most faithfullyattended lay these revolting satellites!

But bantering aside, there is no more engaging subject to the naturalistthan that of animal parasites. Consider the great proportion of animalsthat gain their livelihood by stealing that of others. While a largeproportion of plants are more or less parasitic, they gain, thereby ininterest to the botanist, and many of them are eagerly sought as thechoicest ornaments of our conservatories. Not so with their zoölogicalconfréres. All that is repulsive and uncanny is associated with them, and those who study them, though perhaps among the keenest intellectsand most industrious observers, speak of them without the limits oftheir own circle in subdued whispers or under a protest, and their worksfall under the eyes of the scantiest few. But the study of animalparasites has opened up new fields of research, all bearing mostintimately on those two questions that ever incite the naturalist to themost laborious and untiring diligence--what is life and its origin? Thesubjects of the alternation of generations, or parthenogenesis, ofembryology and biology, owe their great advance, in large degree, to thestudy of such animals as are parasitic, and the question whether theorigin of species be due to creation by the action of secondary laws ornot, will be largely met and answered by the study of the variedmetamorphoses and modes of growth, the peculiar modification of organsthat adapt them to their strange modes of life, and the consequentvariation in specific characters so remarkably characteristic of thoseanimals living parasitically upon others. [6]

With these considerations in view surely a serious, thoughtful, andthorough study of the louse, in all its varieties and species, isneither belittling nor degrading, nor a waste of time. We venture tosay, moreover, that more light will be thrown on the classification andmorphology of insects by the study of the parasitic species, and otherdegraded, wingless forms that do not always live parasitically, especially of their embryology and changes after leaving the egg, thanby years of study of the more highly developed insects alone. AmongHymenoptera the study of the minute Ichueumons, such as theProctotrupids and Chalcids, especially the egg-parasites; among mothsthe study of the wingless canker-worm moth and Orgyla; among Diptera theflea, bee louse, sheep tick, bat tick, and other wingless flies; amongColeoptera, the Meloë, and singular Stylops and Xenos; among Neuroptera, the snow insect, Boreus, the Podura (Fig. 109) and Lepisma, andespecially the hemipterous lice, will throw a flood of light on theseprime subjects in philosophical entomology. 

[Illustration: 109. Podura. ]

Without farther apology, then, and very dependent on the labors ofothers for our information, we will say a few words on some interestingpoints in the natural history of lice. In the first place, how does thelouse bite? It is the general opinion among physicians, supported byable entomologists, that the louse has jaws, and bites. But while thebird lice (Mallophaga) do have biting jaws, whence the Germans call themskin-eaters (_pelzfresser_), the mouth parts of the genus Pediculus, ortrue louse, resemble in their structure those of the bed-bug (Fig. 110), and other Hemiptera. In its form the louse closely resembles thebed-bug, and the two groups of lice, the Pediculi and Mallophaga, shouldbe considered as families of Hemiptera, though degraded and at the baseof the hemipterous series. The resemblance is carried out in the form ofthe egg, the mode of growth of the embryo, and the metamorphosis of theinsect after leaving its egg. 

[Illustration: 110. Bed-bug. ]

Schiödte, a Danish entomologist, has, it seems to us, forever settledthe question as to whether the louse bites the flesh or sucks blood, anddecides a point interesting to physicians, _i. E. _, that the loathsomedisease called phthiriasis is a nonentity. From this source not onlymany living in poverty and squalor are said to have died, but also menof renown, among whom Denny in his work on the Anoplura, or lice, ofGreat Britain, mentions the name of "Pheretima, as recorded byHerodotus, Antiochus Epiphanes, the Dictator Sylla, the two Herods, theEmperor Maximian, and Phillip the Second. " Schiödte, in his essay "OnPhthirius, and on the Structure of the Mouth in Pediculus" (Annals andMagazine of Natural History, 1866, page 213), says that these statementswill not bear examination, and that this disease should be placed on the"retired list, " for such a malady is impossible to be produced by simplyblood-sucking animals, and that they are only the disgusting attendantson other diseases. Our author thus describes the mouth parts of thelouse. 

"Lice are no doubt to be regarded as bugs, simplified in structure andlowered in animal life in accordance with their mode of living asparasites, being small, flattened, apterous, myopic, crawling andclimbing, with a conical head, moulded as it were to suit the rugositiesof the surface they inhabit, provided with a soft, transversely furrowedskin, probably endowed with an acute sense of feeling, which can guidethem in that twilight in which their mode of life places them. Thepeculiar attenuation of the head in front of the antennæ at oncesuggests to the practised eye the existence of a mouth adapted forsuction. This mouth differs from that of the Hemiptera (bed-bug, etc. )generally, in the circumstance that the labium is capable of beingretracted into the upper part of the head, which therefore presents alittle fold, which is extended when the labium is protruded. In order tostrengthen this part, a flat band of chitine is placed on the undersurface, just as the shoemaker puts a small piece of gutta-percha intothe back of an India-rubber shoe; as, however, the chitine is not veryelastic, this band is rather thinner in the middle, in order that it maybend and fold a little when the skin is not extended by the lower lip. The latter consists, as usual, of two hard lateral pieces, of which thefore ends are united by a membrane so that they form a tube, of whichthe interior covering is a continuation of the elastic membrane in thetop of the head; inside its orifice there are a number of small hooks, which assume different positions according to the degree of protrusion;if this is at its highest point the orifice is turned inside out, like acollar, whereby the small hooks are directed backwards, so that they canserve as barbs. These are the movements which the animal executes afterhaving first inserted the labium through a sweat-pore. When the hookshave got a firm hold, the first pair of setæ (the real mandiblestransformed) are protruded; these are, towards their points, united by amembrane so as to form a closed tube, from which, again, is inserted thesecond pair of setæ, or maxillæ, which in the same manner aretransformed into a tube ending in four small lobes placed crosswise. Itfollows that when the whole instrument is exserted, we perceive a longmembranous flexible tube hanging down from the labium, and along thewalls of this tube the setiform mandibles and maxillæ in the shape oflong narrow bands of chitine. In this way the tube of suction can bemade longer or shorter as required, and easily adjusted to the thicknessof the skin in the particular place where the animal is sucking, wherebyaccess to the capillary system is secured at any part of the body. It isapparent, from the whole structure of the instrument, that it is by nomeans calculated on being used as a sting, but is rather to be comparedto a delicate elastic probe, in the use of which the terminal lobesprobably serve as feelers. As soon as the capillary system is reached, the blood will at once ascend into the narrow tube, after which thecurrent is continued with increasing rapidity by means of the pulsationof the pumping ventricle and the powerful peristaltic movement of thedigestive tube. "

[Illustration:[7]111. Mouth of the Louse. ]

If we compare the form of the louse (Fig. 112, Pediculus capitis, thehead louse; Fig. 113, P. Vestimenti, the body louse) with the youngbed-bug as figured by Westwood (Modern Classification of Insects, ii, . P. 475) we shall see a very close resemblance, the head of the young Cimexbeing proportionally larger than in the adult, while the thorax issmaller, and the abdomen is more ovate, less rounded; moreover the bodyis white and partially transparent. 

[Illustration: 113. Body Louse. ]

[Illustration: 112. Head Louse. ]

Under a high power of the microscope specimens treated with dilutedpotash show that the mandibles and maxillæ arise near each other in themiddle of the head opposite the eyes, their bases slightly diverging. Thence they converge to the mouth, over which they meet, and beyond arefree, being hollow, thin bands of chitine, meeting like the maxillæ, ortongue, of butterflies to form a hollow tube for suction. The mandibleseach suddenly end in a curved, slender filament, which is probably usedas a tactile organ to explore the best sites in the flesh of theirvictim for drawing blood. On the other hand the maxillæ, which are muchnarrower than the mandibles, become rounded towards the end, bristlelike, and tipped with numerous exceedingly fine barbs, by which the buganchors itself in the flesh, while the blood is pumped through themandibles. The base of the large, tubular labium, or beak, whichensheathes the mandibles and maxillæ, is opposite the end of the clypeusor front edge of the upper side of the head, and at a distance beyondthe mouth equal to the breadth of the labium itself. The labium, whichis divided into three joints, becomes flattened towards the tip, whichis square, and ends in two thin membranous lobes, probably endowed witha slight sense of touch. On comparing these parts with those of thelouse, it will be seen how much alike they are with the exception of thelabium, a very variable organ in the Hemiptera. From the long sucker ofthe Pediculus, to the stout chitinous jaws of the Mallophaga, or birdlice, is a sudden transition, but on comparing the rest of the head andbody it will be seen that the distinction only amounts to a family one, though Burmeister placed the Mallophaga among the Orthoptera(grasshoppers and crickets) on account of the mandibles being adaptedfor biting. It has been a common source of error to depend too much uponone or a single set of organs. Insects have been classified oncharacters drawn from the wings, or the number of the joints of thetarsi, or the form of the mouth parts. We must take into account inendeavoring to ascertain the limits of natural groups, as the internalanatomy and the embryology and metamorphosis of insects, before we canhope to obtain a natural classification. 

The family of bird lice is a very extensive one, embracing many genera, and several hundred species. One or more species infest the skin of allour domestic and wild mammals and birds, some birds sheltering beneaththeir feathers four or five species of lice. Before giving a hastyaccount of some of our more common species; we will give a sketch of theembryological history of the lice, with special reference to thestructure of the mouth parts. 

[Illustration: 114. Embryo of the Louse. ]

[Illustration: 115. Mouth Parts of the Louse. ]

The eggs (Fig. 114, egg of the head louse) are long, oval, somewhatpear-shaped, with the hinder end somewhat pointed, while the anteriorend is flattened, and bears little conical micropyles (_m_, minuteorifices for the passage of the spermatozoa into the egg), which vary inform in the different species and genera; the opposite end of the egg isprovided with a few bristles. The female attaches her eggs to the hairsor feathers of her host. 

[Illustration: 116. Mouth Parts of the Louse. ]

[Illustration: 118. Mouth Parts of Louse. ]

[Illustration: 117. Mouth Parts of Louse. ]

After the egg has been fertilized by the male, the blastoderm, orprimitive skin, forms, and subsequently two layers, or embryonalmembranes, appear; the outer is called the amnion (Fig. 114, _am_), while the inner visceral membrane (_db_) partially wraps the rude formof the embryo in its folds. The head (_vk_) of the embryo is nowdirected towards the end of the egg on which the hairs are situated;afterwards the embryo revolves on its axis and the head lies next to theopposite end of the egg. Eight tubercles bud out from the under side ofthe head, of which the foremost and longest are the antennæ (_as_), those succeeding are the mandibles, maxillæ, and second maxillæ, orlabium. Behind them arise six long, slender tubercles forming the legs, and the primitive streak rudely marks the lower wall of the thorax andabdomen not yet formed. Figure 115 represents the head and mouth partsof the embryo of the same louse; _vk_ is the forehead, or clypeus;_ant_, the antennæ; _mad_, the mandibles; _max_1, thefirst pair of maxillæ, and _max_^2, the second pairof maxillæ, or labium. Figure 116 represents the mouth parts of thesame insect a little farther advanced, with the jaws and labiumelongated and closely folded together. Figure 117 represents the samestill farther advanced; the mandibles (_mad_) are sharp, and resemblethe jaws of the Mallophaga; and the maxillæ (_max_^1) and labium(_max_^2) are still large, while afterwards the labium becomes nearlyobsolete. Figure 118 represents a front view of the mouth parts of abird louse, Goniodes; _lb_, is the upper lip, or labrum, lying under theclypeus; _mad_, the mandibles; max, the maxillæ; _l_, the lyre-formedpiece; and _pl_, the "plate. "

[Illustration: 119. Louse of Cow. ]

We will now describe some of the common species of lice found on a fewof our domestic animals, and the mallophagous parasites occurring oncertain mammals and birds. The family Pediculina, or true lice, ishigher than the bird lice, their mouth parts, as well as the structureof the head, resembling the true Hemiptera, especially the bed bug. Theclypeus, or front of the head, is much smaller than in the bird lice, the latter retaining the enlarged forehead of the embryo, it being insome species half as large as the rest of the head. 

All of our domestic mammals and birds are plagued by one or more speciesof lice. Figure 119 represents the Hæmatopinus vituli, which is brownishin color. As the specimen figured came from the Burnett collection ofthe Boston Society of Natural History, together with those of the goatlouse, the louse of the common fowl, and of the cat, they areundoubtedly naturalized here. Quite a different species is the louse ofthe hog (H. Suis, Fig. 120). 

[Illustration: 120. Louse of Hog. ]

The remaining parasites belong to the skin-biting lice, or Mallophaga, and I will speak of the several genera referred to in their naturalorder, beginning with the highest form and that which is nearest alliedto Pediculus. 

[Illustration: 121. Louse of Domestic Fowl. ]

The common barn-yard fowl is infested by a louse that we have calledGoniocotes Burnettii (Fig. 121), in honor of the late Dr. W. I. Burnett, a young and talented naturalist and physiologist, who paid moreattention than any one else in this country to the study of theseparasites, and made a large collection of them, now in the museum of theBoston Society of Natural History. It differs from the G. Hologaster ofEurope, which lives on the same bird, in the short second joint of theantennæ, which are also stouter; and in the long head, the clypeus beingmuch longer and more acutely rounded; while the head is less hollowedout at the insertion of the antennæ. The abdomen is oval, and one-halfas wide as long, with transverse, broad, irregular bands along the edgesof the segments. The mandibles are short and straight, two toothed. Thebody is slightly yellowish, and variously streaked and banded withpitchy black. The duck is infested by a remarkably slender form (Fig. 122, Philopterus squalidus). Figure 123 represents the louse of the cat, and another species (Fig. 124) of the same genus (Trichodes) lives uponthe goat. 

The most degraded genus is Gyropus. Mr. C. Cook has found Gyropus ovalisof Europe abundant on the Guinea pig. A species is also found on theporpoise; an interesting fact, as this is the only insect we know ofthat lives parasitically on any marine animal. 

[Illustration: 122. Duck Louse. ]

The genus Goniodes (Fig. 125, G. Stylifer, the turkey louse) is of greatinterest from a morphological and developmental point of view, as theantennæ are described and figured by Denny as being "in the malescheliform (Fig. 126, _a_, male; _b_, female); the first joint being verylarge and thick, the third considerably smaller, recurved towards thefirst, and forming a claw, the fourth and fifth very small, arisingfrom the back of the third. " He farther remarks, that "the males of this[which lives on the turkey] and all the other species of Goniodes, usethe first and third joints of the antennæ with great facility, actingthe part of a finger and thumb. " The antennæ of the females are of theordinary form. This hand-like structure, is, so far as we know, withouta parallel among insects, the antennæ of the Hemiptera being almostuniformly filiform, and from two to nine-jointed. The design of thisstructure is probably to enable the male to grasp its consort and alsoperhaps to cling to the feathers, and thus give it a superiority overthe weaker sex in its advances towards courtship. Why is this advantagepossessed by the males of this genus alone? The world of insects, and ofanimals generally abounds in such instances, though existing in otherorgans, and the developmentist dimly perceives in such departures from anormal type of structure, the origin of new generic forms, whether dueat first to a seemingly accidental variation, or, as in this instance, perhaps, to long use as prehensile organs through successive generationsof lice having the antennæ slightly diverging from the typicalcondition, until the present form has been developed. Another generationof naturalists will perhaps unanimously agree that the Creator has thusworked through secondary laws, which many of the naturalists of thepresent day are endeavoring, in a truly scientific and honest spirit ofinquiry, to discover. 

[Illustration: 124. Louse of the Goat. ]

[Illustration: 123. Louse of the Cat. ]

In their claw or leg-like form these male antennæ also repeat in thehead, the general form of the legs, whose prehensile and graspingfunctions they assume. We have seen above that the appendages of thehead and thorax are alike in the embryo, and the present case is aninteresting example of the unity of type of the jointed appendages ofinsects, and articulates generally. 

[Illustration: 120. Antennæ of Goniodes. ]

Another point of interest in these degraded insects is, that the processof degradation begins either late in the life of the embryo or duringthe changes from the larval to the adult, or winged state. An instanceof the latter may be observed in the wingless female of the canker worm, so different from the winged male; this difference is created after thelarval stage, for the caterpillars of both sexes are the same, so far aswe know. So with numerous other examples among the moths. In the louse, the embryo, late in its life, resembles the embryos of other insects, even Corixa, a member of a not remotely allied family. But just beforehatching the insect assumes its degraded louse physiognomy. Thedevelopmentist would say that this process of degradation points tocauses acting upon the insect just before or immediately after birth, inducing the retrogression and retardation of development, and wouldconsider it as an argument for the evolution of specific forms by causesacting on the animal while battling with its fellows in the struggle forexistence, and perhaps consider that the metamorphoses of the animalwithin the egg are due to a reflex action of the modes of life of theancestors of the animal on the embryos of its descendants. 

[Illustration: 125. The Turkey Louse. ]

FOOTNOTES:

[Footnote 5:

 Ha! whare ye gaun, ye crowlin ferlie! Your impudence protects you sairly: I canna say but ye struift rarely, Owre gauze and lace; Tho' faith, I fear ye dine but sparely On sic a place. 

 Ye ugly, creepin, blastic wormer, Detested, shunn'd by saunt and sinner, How dare ye set your fit upon her Sae fine a lady! Gae somewhere else and seek your dinner On some poor body. 

(To a Louse. --Burns. )]

[Footnote 6: We notice while preparing this article that a journal ofParasitology has for some time been issued in Germany--that favored landof specialists. It is the "Zeitschrift fur Parasitenkunde, " edited byDr. E. Hallier and F A. Zurn. 8vo, Jena. ]

[Footnote 7: Figure 111 represents the parts of the mouth in a largespecimen of _Pediculus_ vestimenti, entirely protruding, and seen fromabove, magnified one hundred and sixty times; aa, the summit of the headwith four bristles on each side; _bb_, the chitinous band, and _c_, thehind part of the lower lip, such as they appear through the skin bystrong transmitted light; _dd_, the foremost protruding part of thelower lip (the haustellum); _ee_, the hooks turned outwards; _f_, theinner tube of suction, slightly bent and twisted; the two pairs of jawsare perceived on the outside as thin lines; a few blood globules areseen in the interior of the tube. ]

CHAPTER X. 

THE DRAGON FLY. 

Were we to select from among the insects a type of all that is savage, relentless, and bloodthirsty, the Dragon fly would be our choice. Fromthe moment of its birth until its death, usually a twelve-month, itriots in bloodshed and carnage. Living beneath the waters perhaps elevenmonths of its life, in the larva and pupa states, it is literally awalking pitfall for luckless aquatic insects; but when transformed intoa fly, ever on the wing in pursuit of its prey, it throws off allconcealment, and reveals the more unblushingly its rapacious character. 

Not only do its horrid visage and ferocious bearing frighten children, who call it the "Devil's Darning-needle, " but it even distresses olderpersons, so that its name has become a byword. Could we understand thelanguage of insects, what tales of horror would be revealed! Whattraditions, sagas, fables, and myths must adorn the annals of animallife regarding this Dragon among insects!

To man, however, aside from its bad name and its repulsive aspect, whichits gay trappings do not conceal, its whole life is beneficent. It is ascavenger, being like that class ugly and repulsive, and holdingliterally, among insects, the lowest rank in society. In the water, itpreys upon young mosquitoes and the larvæ of other noxious insects. Itthus aids in maintaining the balance of life, and cleanses the swamps ofmiasmata, thus purifying the air we breathe. During its existence ofthree or four weeks above the waters, its whole life is a continued goodto man. It hawks over pools and fields and through gardens, decimatingswarms of mosquitoes, flies, gnats, and other baneful insects. It is atrue Malthus' delight, and, following that sanguinary philosopher, wemay believe that our Dragon fly is an entomological Tamerlane orNapoleon sent into the world by a kind Providence to prevent too close ajostling among the myriads of insect life. 

We will, then, conquer our repugnance to its ugly looks and savage mien, and contemplate the hideous monstrosity, --as it is useless to deny thatit combines the graces of the Hunchback of Notre Dame and Dickens'Quilp, with certain features of its own, --for the good it does inNature. 

Even among insects, a class replete with forms the very incarnation ofugliness and the perfection of all that is hideous in nature, our Dragonfly is most conspicuous. Look at its enormous head, with its beetlingbrows, retreating face, and heavy under jaws, --all eyes and teeth, --andhung so loosely on its short, weak neck, sunk beneath its enormoushunchback, --for it is wofully round-shouldered, --while its long, thinlegs, shrunken as if from disease, are drawn up beneath its breast, andwhat a hobgoblin it is!

Its gleaming wings are, however, beautiful objects. They form a broadexpanse of delicate parchment-like membrane drawn over an intricatenetwork of veins. Though the body is bulky, it is yet light, and easilysustained by the wings. The long tail undoubtedly acts as a rudder tosteady its flight. 

These insects are almost universally dressed in the gayest colors. Thebody is variously banded with rich shades of blue, green, and yellow, and the wings give off the most beautiful iridescent and metallicreflections. 

During July and August the various species of Libellula and its alliesmost abound. The eggs are attached loosely in bunches to the stems ofrushes and other water-plants. In laying them, the Dragon fly, accordingto Mr. P. R. Uhler's observations, "alights upon water-plants, and, pushing the end of her body below the surface of the water, glues abunch of eggs to the submerged stem or leaf. Libellula auripennis I haveoften seen laying eggs, and I think I was not deceived in my observationthat she dropped a bunch of eggs into the open ditch while balancingherself just a little way above the surface of the water. I have, also, seen her settled upon the reeds in brackish water with her abdomensubmerged in part, and there attaching a cluster of eggs. I feel prettysure that L. Auripennis does not always deposit the whole of her eggs atone time, as I have seen her attach a cluster of not more than a dozensmall yellow eggs. There must be more than one hundred eggs in one ofthe large bunches. The eggs of some of the Agrions are brightapple-green, but I cannot be sure that I have ever seen them in the veryact of oviposition. They have curious habits of settling upon leaves andgrass growing in the water, and often allow their abdomens to fall belowthe surface of the water; sometimes they fly against the surface, but Inever saw what I could assert to be the projecting of the eggs from thebody upon plants or into the water. The English entomologists assertthat the female Agrion goes below the surface to a depth of severalinches to deposit eggs upon the submerged stems of plants. " The Agrions, however, according to Lucaze Duthiers, a French anatomist, make, withthe ovipositor, a little notch in the plant upon which they lay theireggs. 

[Illustration: 127. Under side of head of Diplax, with the labium ormask fully extended. _x_, _x_', _x_''the three subdivisions of thelabium. _y_, the maxillæ or second pair of jaws. ]

These eggs soon hatch, probably during the heat of summer. The larva isvery active in its habits, being provided with six legs, attached to thethorax, on the back of which are the little wing-pads, or rudimentarywings. The large head is provided with enormous eyes, while a pair ofsimple, minute eyelets (ocelli) are placed near the origin of the smallbristle-like feelers, or antennæ. Seen from beneath, instead of theformidable array of jaws and accessory organs commonly observed in mostcarnivorous larvæ, we see nothing but a broad, smooth mask covering thelower part of the face; as if from sheer modesty our young Dragon flywas endeavoring to conceal a gape. But wait a moment. Some unwary insectcomes within striking distance. The battery of jaws is unmasked, andopens upon the victim. This mask (Fig. 127) is peculiar to the young, or larva and pupa of the Dragon fly. It is the labium, or under lipgreatly enlarged, and armed at the broad spoon-shaped extremity (Fig. 127, _x_) with two sharp hooks, adapted for seizing and retaining itsprey. At rest, the terminal half is so bent up as to conceal the face, and thus the creature crawls about, to all appearance, the most innocentand lamb-like of insects. 

[Illustration: 128. Abdominal valves; _a_, side view. ]

Not only does the immature Dragon fly walk over the bottom of the poolor stream it inhabits, but it can also leap for a considerable distance, and by a most curious contrivance. By a syringe-like apparatus lodged inthe end of the body, it discharges a stream of water for a distance oftwo or three inches behind it, thus propelling the insect forwards. Thisapparatus combines the functions of locomotion and respiration. Thereare, as usual, two breathing pores (stigmata) on each side of thethorax. But the process of breathing seems to be mostly carried on inthe tail. The tracheæ are here collected in a large mass, sending theirbranches into folds of membrane lining the end of the alimentary canal, and which act like a piston to force out the water. The entrance to thecanal is protected by three to five triangular horny valves (Fig. 128, 9, 10, 128 _a_, side view), which open and shut at will. When open, thewater flows in, bathing the internal gill-like organs, which extract theair from the water, which is then suddenly expelled by a strong musculareffort. 

[Illustration: 129. Agrion; _b_, False Gill of Larva. ]

In the smaller forms, such as Agrion (A. Saucium, Fig. 129; Fig. 129_b_, side view of false gill, showing but one leaf), the respiratoryleaves, called the tracheary, or false-gills, are not enclosed withinthe body, but form three broad leaves, permeated by tracheæ, orair-vessels. They are not true gills, however, as the blood is notaerated in them. They only absorb air to supply the tracheæ, whichaerate the blood only within the general cavity of the body. These falsegills also act as a rudder to aid the insect in swimming. 

It is interesting to watch the Dragon flies through theirtransformations, as they can easily be kept in aquaria. Little, almostnothing, is known regarding their habits, and any one who can spend thenecessary time and patience in rearing them, so as to trace up thedifferent stages from the larva to the adult fly, and describe andfigure them accurately, will do good service to science. 

[Illustration: 130. Pupa of Cordulia. ]

Mr. Uhler states that at present we know but little of the young stagesof our species, but the larva and pupa of the Libellulas may be alwaysknown from the Æschnas by the shorter, deeper and more robust form, andgenerally by their thick clothing of hair. Figure 130 represents thepupa of Cordulia lateralis, and figure 131 that of a Dragon fly referreddoubtfully to the genus Didymops. For descriptions and figures of otherforms the reader may turn to Mr. Louis Cabot's essay "On the ImmatureState of the Odonata, " published by the Museum of Comparative Zoology atCambridge. 

[Illustration: 131. Pupa of Didymops?]

The pupa scarcely differs from the larva, except in having largerwing-pads (Fig. 132). It is still active, and as much of a gourmand asever. When the insect is about to assume the pupa state, it moults itsskin. The body having outgrown the larva skin, by a strong musculareffort a rent opens along the back of the thorax, and the insect havingfastened its claws into some object at the bottom of the pool, the pupagradually works its way out of the larva-skin. It is now considerablylarger than before. Immediately after this tedious operation, its bodyis soft, but the crust soon hardens. This change, with most species, probably occurs early in summer. 

[Illustration: 132. Pupa of Æschna. ]

When about to change into the adult fly, the pupa climbs up some plantnear the surface of the water. Again its back yawns wide open, and fromthe rent our Dragon fly slowly emerges. For an hour or more, it remainstorpid and listless, with its flabby, soft wings remaining motionless. The fluids leave the surface, the crust hardens and dries, rich andvaried tints appear, and our Dragon fly rises into its new world oflight and sunshine a gorgeous, but repulsive being. Tennyson thusdescribes these changes in "The Two Voices":--

 To-day I saw the Dragon fly Come from the wells where he did lie. An inner impulse rent the veil Of his old husk: from head to tail Came out clear plates of sapphire mail. 

 He dried his wings; like gauze they grew; Through crofts and pastures wet with dew A living flash of light he flew. 

Of our more common, typical forms of Dragon flies, we figure a few, commonly observed during the summer. The three-spotted Dragon fly(Libellula trimaculata), of which figure 133 represents the male, is socalled from the three dark clouds on the wings of the female. But theopposite sex differs in having a dark patch at the front edge of thewings, and a single broad cloud just beyond the middle of the wing. 

Libellula quadrimaculata, the four-spotted Dragon fly (Fig. 134), isseen on the wing in June, flying through dry pine woods far from anystanding water. 

[Illustration: 133. Libellula trimaculata, male. ]

[Illustration: 134. Libellula quadrimaculata. ]

The largest of our Dragon flies are the "Devil's Darning-needles, "Eschna heros and grandis, seen hawking about our gardens till dusk. Theyfrequently enter houses, carrying dismay and terror among the children. The hind-body is long and cylindrical, and gaily colored with brightgreen and bluish bands and spots. 

[Illustration: 135. Diplax Berenice, male. ]

[Illustration: 136. Diplax Berenice, female. ]

[Illustration: 137. Larva of Diplax. ]

One of our most common Dragon flies is the ruby Dragon fly, Diplaxrubicundula, which is yellowish-red. It is seen everywhere flying overpools, and also frequents dry sunny woods and glades. Another commonform is Diplax Berenice (Fig. 135 male, Fig. 136 female. Theaccompanying cut (137) represents the larva, probably of this species, according to Mr. Uhler. ) It is black, the head blue in front, spottedwith yellow, while the thorax and abdomen are striped with yellow. Thereare fewer stripes on the body of the male, which has only four largeyellow spots on each side of the abdomen. Still another pretty speciesis Diplax Elisa (Fig. 138). It is black, with the head yellowish andwith greenish-yellow spots on the sides of the thorax and base of theabdomen. There are three dusky spots on the front edge of each wing, anda large cloud at the base of the hind pair towards the hind angles ofthe wing. 

Rather a rare form, and of much smaller stature is the Nannophya bella(Fig. 138, female). It was first detected in Baltimore, and weafterwards found it not unfrequently by a pond in Maine. Its abdomen isunusually short, and the reticulations of the wings are large andsimple. The female is black, while the male is frosted over with awhitish powder. Many more species of this family are found in thiscountry, and for descriptions of them we would refer the reader to Dr. Hagen's "Synopsis of the Neuroptera of North America, " published by theSmithsonian Institution. 

[Illustration: 138. Diplax Elisa. ]

[Illustration: 139. Nannophya bella. ]

[Illustration: 140. May Fly. ]

The Libellulidæ, or family of Dragon flies, and the Ephemeridæ, or Mayflies (Fig. 140), are the most characteristic of the Neuroptera, orveiny-winged insects. This group is a most interesting one to thesystematist, as it is composed of so many heterogeneous forms which itis almost impossible to classify in our rigid and at present necessarilyartificial systems. We divide them into families and sub-families, genera and sub-genera, species and varieties, but there is an endlessshifting of characters in these groups. The different groups would seemwell limited after studying certain forms, when to the systematist'ssorrow, here comes a creature, perhaps mimicking an ant, or aphis, orother sort of bug, or even a butterfly, and for which they would bereadily mistaken by the uninitiated. Bibliographers have gone mad overbooks that could not be classified. Imagine the despair of aninsect-hunter and entomophile, as he sits down to his box of driedneuroptera. He seeks for a true neuropter in the white ant before him, but its very form and habits summon up a swarm of true ants; and thenthe little wingless book louse (Atropos, Fig. 141) scamperingirreverently over the musty pages of his Systema Naturæ, reminds him ofthat closest friend of man--Pediculus vestimenti. Again, his studieslead him to that gorgeous inhabitant of the South, the butterfly-likeAscalaphus, with its resplendent wings, and slender, knobbed antennæ somuch like those of butterflies, and visions of these beautiful insectsfill his mind's eye; or sundry dun-colored caddis flies, modest, delicate neuroptera, with finely fringed wings and slender feelers, create doubts as to whether they are not really allies of the clothesmoth, so close is the resemblance. 

[Illustration: 141. Death Tick. ]

Thus the student is constantly led astray by the wanton freaks Natureplays, and becomes sceptical as regards the truth of a natural system, though there is one to be discovered; and at last disgusted with thestiff and arbitrary systems of our books, --a disgust we confess mostwholesome, if it only leads him into a closer communion with nature. Thesooner one leaves those maternal apron-strings, --books, --and learns toidentify himself with nature, and thus goes out of himself to affiliatewith the spirit of the scene or object before him, --or, in other words, cultivates habits of the closest observation and most patientreflection, --be he painter or poet, philosopher or insect-hunter of lowdegree, he will gain an intellectual strength and power of interpretingnature, that is the gift of true genius. 

[Illustration: The Ant Lion and adult. ]

CHAPTER XI. 

MITES AND TICKS. 

But few naturalists have busied themselves with the study of mites. Thehonored names of Hermann, Von Heyden, Dugés, Dujardin and Pagenstecher, Nicolet, Koch and Robin, and the lamented Claparède of Geneva, lead thesmall number who have published papers in scientific journals. Afterthese, and except an occasional note by an amateur microscopist whooccasionally pauses from his "diatomaniacal" studies, and looks upon amite simply as a "microscopic object, " to be classed in his micrographicVade Mecum with mounted specimens of sheep's wool, and the hairs ofother quadrupeds, a distorted proboscis of a fly, and podura scales, weread but little of mites and their habits. But few readers of ournatural history text-books learn from their pages any definite factsregarding the affinities of these humble creatures, their organizationand the singular metamorphosis a few have been known to pass through. Weshall only attempt in the present article to indicate a few of thetypical forms of mites, and sketch, with too slight a knowledge to speakwith much authority, an imperfect picture of their appearance and modesof living. 

Mites are lowly organized Arachnids. This order of insects is dividedinto the Spiders, the Scorpions, the Harvestmen and the Mites (Acarina). They have a rounded oval body, without the usual division between thehead-thorax and abdomen observable in spiders, the head-thorax andabdomen being merged in a single mass. There are four pairs of legs, andthe mouth parts consist, as seen in the adjoining figure of a young tick(Fig. 142, young Ixodes albipictus), of a pair of maxillæ (_c_), whichin the adult terminates in a two or three-jointed palpus, or feeler; apair of mandibles (_b_), often covered with several rows of fine teeth, and ending in three or four larger hooks and a serrated labium (_a_). These parts form a beak which the mite or tick insinuates into the fleshof its host, upon the blood of which it subsists. While many of themites are parasitic on animals, some are known to devour the eggs ofinsects and other mites, thrusting their beaks into the egg, and suckingthe contents. We have seen a mite (Nothrus ovivorus, Fig. 143) busilyengaged in destroying the eggs of a moth like that of the Canker worm, and Dr. Shimer has observed the Acarus? malus sucking the eggs of theChinch bug. I have also observed another mite devouring the Aphides onthe rose leaves in my garden, so that a few mites may be set down asbeneficial to vegetation. While a few species are injurious to man, thelarger part are beneficial, being either parasitic and baneful to othernoxious animals, or more directly useful as scavengers, removingdecaying animal and vegetable substances. 

[Illustration: 142, Ixodes albipictus and young. [8]]

The transformations of the mites are interesting to the philosophiczoologist, since the young of certain forms are remarkably differentfrom the adults, and in reaching the perfect state the mite passesthrough a metamorphosis more striking than that of many insects. Theyoung on leaving the egg have six legs, as we have seen in the case ofthe Ixodes. Sometimes, however, as, for example, in the larva, as we maycall it, of a European mite, Typhlodromus pyri, the adult of which, according to A. Scheuten, is allied to Acarus, and lives under theepidermis of the leaves of the pear in Europe (while Mr. T. Taylor, ofthe Department of Agriculture at Washington, has found a species in thepear leaves about Washington, and still another form in peach leaves), there are but two pairs of legs present, and the body is long, cylindrical and in a degree worm-like. 

I have had the good fortune to observe the different stages of a birdmite, intermediate in its form between the Acarus and Sarcoptes, or Itchmite. On March 6th, Mr. C. Cooke called my attention to certain littlemites which were situated on the narrow groove between the main stem ofthe barb and the outer edge of the barbules of the feathers of the DownyWoodpecker, and subsequently we found the other forms in the down underthe feathers. These long worm-like mites were evidently the young of asingular Sarcoptes-like mite, as they were found on the same specimen ofWoodpecker at about the same date, and it is known that the growth ofmites is rapid, the metamorphoses, judging by the information which wenow possess, occupying usually but a few days. 

[Illustration: 143. Egg-eating Mite. ]

The young (though there is, probably, a still earlier hexapodous stage)of this Sarcoptid has an elongated, oblong, flattened body, with fourshort legs, provided with a few bristle-like hairs, and ending in astalked sucker, by aid of which the mite is enabled to walk over smooth, hard surfaces. The body is square at the end, with a slight medianindentation, and four long bristles of equal length. They remainedmotionless in the groove on the barb of the feather, and when removedseemed very inert and sluggish. A succeeding stage of this mite, whichmay be called the pupal, is considerably smaller than the larva andlooks somewhat like the adult, the body having become shorter andbroader. The adult is a most singular form, its body being rudely ovate, with the head sunken between the fore legs, which are considerablysmaller than the second pair, while the third pair are twice as large asthe second pair, and directed backwards, and the fourth pair are verysmall, not reaching the extremity of the body, which is deeply cleft andsupports four long bristles on each side of the cleft, while otherbristles are attached to the legs and body, giving the creature, originally ill-shapen, a haggard, unkempt appearance. The two stigmataor breathing pores open near the cleft in the end of the body, and theexternal opening of the oviduct is situated between the largest andthird pair of legs. No males were observed. In a species of Acarus(Tyroglyphus), somewhat like the Cheese mite, which we have alive atthe time of writing, in a box containing the remains of a Lucanus larva, which they seem to have consumed, as both young and old are swarmingthere by myriads, the young are oval and like the adults, except thatthey are six-legged, the fourth pair growing out after a succeedingmoult. 

Such is a brief summary of what has been generally known regarding themetamorphoses of a few species of mites. In a few kinds no males havebeen found; the females have been isolated after being hatched, and yethave been known to lay eggs, which produced young without theinterposition of the males. This parthenogenesis has been noticed inseveral species. 

[Illustration: 144. Cheyletus. ]

These insects often suddenly appear in vast numbers on various articlesof food and about houses, so as to be very annoying. Mr. J. J. H. Gregory, of Marblehead, Mass. , has found a mite allied to the Europeanspecies here figured (Fig. 144) very injurious to the seeds of thecabbage, which it sucked dry. This is an interesting form, and we havecalled it Cheyletus seminivorus It is of medium size, and especiallynoticeable from the tripartite palpi, which are divided into an outer, long, curved, claw-like lobe, with two rounded teeth at the base, andtwo inner, slender lobes pectinated on the inner side, the thirdinnermost lobe being minute. The beak terminates in a sharp blade-likepoint. 

We have received a Cheyletus-like mite, said to have been "extractedfrom the human face" in New Orleans. The body is oblong, square behind;the head is long and pointed, while the maxillæ end in a long, curved, toothed, sickle-like blade. That this creature has the habits of theitch mite is suggested by the curious, large, hair-like spines withwhich the body and legs are sparsely armed, some being nearly half aslong as the body. These hairs are covered with very fine spinules. Thoseon the end of the body are regularly spoon-shaped. These strange hairs, which are thickest on the legs, probably assisted the mite in anchoringitself in the skin of its host. We have read no account of this strangeand interesting form. It is allied to the Acaropsis Mericourti whichlives in the human face. 

A species, "apparently of the genus Gamasus, " according to Dr. Leidy, has been found living in the ear (at the bottom of the external auditorymeatus, and attached to the membrana tympani) of steers. "Whether thismite is a true parasite of the ear of the living ox, or whether itobtained access to the position in which it was found after the death ofthe ox in the slaughter house, has not yet been determined. "

We will now give a hasty glance at the different groups of mites, pausing to note those most interesting from their habits or relation toman. 

The most highly organized mite (and by its structure most closely alliedto the spider) is the little red garden mite, belonging to the genusTrombidium, to which the genus Tetranychus is also nearly related. Ourown species of the former genus have not been "worked up, " or in otherwords identified and described, so that whether the European T. Holosericeum Linn. Is our species or not, we cannot tell. The larvæ ofthis and similar species are known to live parasitically upon Harvestmen(Phalangium), often called Daddy-long-legs; and upon Aphides, grasshoppers and other insects. Mr. Riley has made known to us throughthe "American Naturalist" (and from his account our information istaken), the habits of certain young of the garden mite (Trombidium)which are excessively annoying in the Southwestern States. The first isthe Leptus? Americanus (Fig. 145), or American Harvest mite. It is onlyknown as yet in the larval or Leptus state, when it is of the formindicated in the cut, and brick red in color. "This species is barelyvisible with the naked eye, moves readily and is found more frequentlyupon children than upon adults. It lives mostly on the scalp and underthe arm pits, but is frequently found on the other parts of the body. Itdoes not bury itself in the flesh, but simply insinuates the anteriorpart of the body just under the skin, thereby causing intenseirritation, followed by a little red pimple. As with our common ticks, the irritation lasts only while the animal is securing itself, and itspresence would afterwards scarcely be noticed but for the pimple whichresults. "

[Illustration: 145 _a. _ American Harvest Mite; _b. _ Irritating HarvestMite; the dots underneath indicating the natural size. ]

The second species (Fig. 145 _b_, Leptus? irritans) is also only knownin the Leptus stage. It is evidently the larva of a distinct genus fromthe other form, having enormous maxillæ and a broad body; it is alsobrick red. Mr. Riley says that "this is the most troublesome and, perhaps, best known of the two, causing intense irritation and swellingon all parts of the body, but more especially on the legs and around theankles. Woe betide the person who, after bathing in the Mississippianywhere in this latitude, is lured to some green dressing-spot of weedsor grass! He may, for the time, consider himself fortunate in gettingrid of mud and dirt, but he will afterwards find to his sorrow that heexchanged them for something far more tenacious in these microscopicHarvest-mites. If he has obtained a good supply of them, he will in afew hours begin to suffer from severe itching, and for the next two orthree days will be likely to scratch until his limbs are sore. 

"With the strong mandibles and the elbowed maxillæ which act like arms, this mite is able to bury itself completely in the flesh, therebycausing a red swelling with a pale pustulous centre containing waterymatter. If, in scratching, he is fortunate enough to remove the mitebefore it enters, the part soon heals. But otherwise the irritationlasts for two, three or four days, the pustulous centre reappearing asoften as it is broken. 

"The animal itself, on account of its minute size, is seldom seen, andthe uninitiated, when first troubled with it, are often alarmed at thesymptoms and at a loss to account for them. Fortunately these littleplagues never attach themselves to persons in such immense numbers as dosometimes young or so-called 'seed' ticks; but I have known cases where, from the irritation and consequent scratching, the flesh had theappearance of being covered with ulcers; and in some localities, wherethese pests most abound, sulphur is often sprinkled during 'jigger'season in the boots or shoes as a protection. 

"Sulphur ointment is the best remedy against the effects of either ofthese mites, though when that cannot be obtained, saleratus water andsalt water will partially allay the irritation. 

"The normal food of either must, apparently, consist of the juices ofplants, and the love of blood proves ruinous to those individuals whoget a chance to indulge it. For unlike the true Jigger, the female ofwhich deposits eggs in the wound she makes, these Harvest-mites have noobject of the kind, and when not killed by the hands of those theytorment, they soon die victims to their sanguinary appetite. "

[Illustration: 146. Astoma of the Fly. ]

Another Leptus-like form is the parasite of the fly, described by Mr. Riley under the name of Astoma? muscarum (Fig. 146). How nearly alliedit is to the European Astoma parasiticum we have not the means ofjudging. 

The European Tetranychus telarius Linn. , or web-making mite, spins largewebs on the leaves of the linden tree. Then succeed in the natural orderthe water mites (Hydrachna), which may be seen running over submergedsticks and on plants, mostly in fresh water, and rarely on the bordersof the sea. The young after leaving the egg differ remarkably from theadults, so as to have been referred to a distinct genus (Achlysia) bythe great French naturalist, Audouin. They live as parasites on variouswater insects, such as Dytiscus, Nepa and Hydrometra, and when maturelive free in the water, though Von Baer observed an adult Hydrachnaconcharum living parasitically on the gills of the fresh-water mussel, Anodon. The species are of minute size. Collectors of beetles often meetwith a species of Uropoda attached firmly to their specimens ofdung-inhabiting or carrion beetles. It is a smoothly polished, round, flattened mite, with short, thick legs, scarcely reaching beyond thebody. 

[Illustration: 147. Cattle Tick. ]

We now come to the Ticks, which comprise the largest mites. The genusArgas closely resembles Ixodes. Gerstaecker states that the ArgasPersicus is very annoying to travellers in Persia. The habits of thewood ticks (Ixodes) are well known. Travellers in the tropics speak ofthe intolerable torment occasioned by these pests which, occurringordinarily on shrubs and trees, attach themselves to all sorts ofreptiles, beasts and cattle, and even man himself as he passes by withintheir reach. Sometimes cases fall within the practice of the physician, who is called to remove the tick, which is found sometimes literallyburied beneath the skin. Mr. J. Stauffer writes me, that "on June 23dthe daughter of Abraham Jackson (colored), playing among the leaves in awood, near Springville, Lancaster County, Penn. , on her return homecomplained of pain in the arm. No attention was paid to it till the nextday, when a raised tumor was noticed, a small portion protruding throughthe skin, apparently like a splinter of wood. The child was taken to Dr. Morency, who applied the forceps, and after considerable pain to thechild, and labor to himself, extracted a species of Ixodes, nearlyone-quarter of an inch long, and of an oval form and brown mahoganycolor, with a metallic spot, like silver bronze, centrally on the dorsalregion. " This tick proved, from Mr. Stauffer's figures, to be, withoutdoubt, Ixodes unipunctata. It has also been found in Massachusetts byMr. F. G. Sanborn. 

Another species is the Ixodes bovis (Fig. 147), the common cattle tickof the Western States and Central America. It is very annoying to hornedcattle, gorging itself with their blood, but is by no means confined tothem alone, as it lives indifferently upon the rattlesnake, the iguana, small mammals and undoubtedly any other animal that brushes by itslurking-place in the forest. It is a reddish, coriaceous, flattened, seed-like creature, with the body oblong oval, and contracted justbehind the middle. When fully grown it measures from a quarter to halfan inch in length. We have received it from Missouri, at the hands ofMr. Riley, and Mr. J. A. McNiel has found it very abundantly on hornedcattle on the western coast of Nicaragua. 

We now come to the genus Acarus (Tyroglyphus), of which the cheese andsugar mites are examples. Some species of Acarian mites have been foundin the lungs and blood-vessels, and even the intestinal canal of certainvertebrates, while the too familiar itch insect lurks under the skin ofthe hand and other parts of the body of certain uncleanly human bipeds. 

[Illustration: 148. Sugar Mite. ]

Many people have been startled by statements in newspapers and moreauthoritative sources, as to the immense numbers of mites (Acarussacchari, Fig. 148) found in unrefined or raw sugar. According to Prof. Cameron, of Dublin, as quoted in the "Journal of the FranklinInstitute, " for November, 1868, "Dr. Hassel (who was the first to noticetheir general occurrence in the raw sugar sold at London) found them ina living state in no fewer than sixty-nine out of seventy-two samples. He did not detect them in a single specimen of refined sugar. In aninferior sample of raw sugar, examined in Dublin by Mr. Cameron, hereports finding five hundred mites in ten grains of sugar, so that in apound's weight occurred one hundred thousand of these little creatures, which seem to have devoted themselves with a martyr-like zeal to theadulteration of sugar. They appear as white specks in the sugar. Thedisease known as grocer's itch is, undoubtedly, due to the presence ofthis mite, which, like its ally the Sarcoptes, works its way under theskin of the hand, in this case, however, of cleanly persons. Mr. Cameronstates that "the kind of sugar which is both healthful and economical, is the dry, large-grained and light-colored variety. "

Closely allied to the preceding, is the Cheese mite (Acarus siro Linn. ), which often abounds in newly made cheese. Lyonet states that duringsummer this mite is viviparous. Acarus farinæ DeGeer, as its nameindicates, is found in flour. Other species have been known to occur inulcers. 

[Illustration: 149. Mange Mite. ]

We should also mention the Mange insect of the horse (Psoroptes equi, Fig. 149, much enlarged; _a_, head more magnified). According to Prof. Verrill it is readily visible to the naked eye and swarms on horsesafflicted with the mange, which is a disease analogous to the itch inman. It has a soft, depressed body, spiny beneath at the base of thelegs and on the thorax. One or both of the two posterior pairs of feetbear suckers, and all are more or less covered with long, slender hairs. This insect may be destroyed by the same remedies as are used for liceand for the human itch. The best remedy is probably a solution ofsulphuret of potassium. 

[Illustration: 150. Itch Mite. ]

[Illustration: 151. Nose Mite. ]

The itch insect (Sarcoptes scabiei, Fig. 150) was first recognized by anArabian author of the twelfth century, as the cause of the disease whichresults from its attacks. The body of the insect is rounded, with thetwo hind pair of feet rudimentary and bearing long hairs. It buriesitself in the skin on the more protected parts of the body, and by itspunctures maintains a constant irritation. Other species are known toinfest the sheep and dog. Another singular mite is the Demodexfolliculorum (Fig. 151), which was discovered by Dr. Simon, of Berlin, buried in the diseased follicles of the wings of the nose in man. It isa long, slender, worm-like form, with eight short legs, and in thelarva state has six legs. This singular form is one of the lowest andmost degraded of the order of Arachnids. A most singular mite wasdiscovered by Newport on the body of a larva of a wild bee, anddescribed by him under the name of Heteropus ventricosus. The body ofthe fully formed female is long and slender. After attaining this form, its small abdomen begins to enlarge until it assumes a globular form, and the mass of mites look like little beads. Mr. Newport was unable todiscover the male, and thought that this mite was parthenogenous. Itwill be seen that the adult Demodex retains the elongated, worm-likeappearance of the larva of the higher mites, such as Typhlodromus. Thisis an indication of its low rank, and hints of a relationship to theTardigrades and the Pentastoma, the latter being a degraded mite, andthe lowest of its order, living parasitically within the bodies of otheranimals. 

[Illustration: Harvestman. ]

FOOTNOTES:

[Footnote 8: The figure at the bottom on the left represents the adult, fully-gorged tick. ]

CHAPTER XII. 

BRISTLE-TAILS AND SPRING-TAILS. 

The Thysanura, as the Poduras and their allies, the Lepismas, arecalled, have been generally neglected by entomologists, and but fewnaturalists have paid special attention to them. [9] Of all thosemicroscopists who have examined Podura scales as test objects, we wonderhow many really know what a Podura is?

In preparing the following account I have been under constantindebtedness to the admirable and exhaustive papers of Sir John Lubbock, in the London "Linnæan Transactions" (vols. 23, 26 and 27). Entomologists will be glad to learn that he is shortly going to presswith a volume on the Poduras, which, in distinction from the Lepismas, to which he restricts the term Thysanura, he calls Collembola, inallusion to the sucker-like tubercle situated on the under side of thebody, which no other insects are known to possess. 

The group of Bristle-tails, as we would dub the Lepismas in distinctionfrom the Spring-tails, we will first consider. They are abundant in theMiddle States under stones and leaves in forests, and northward arecommon in damp houses, while one beautiful species that we have nevernoticed elsewhere, is our "cricket on the hearth, " abounding in thechinks and crannies of the range of our house, and also in closets, where it feeds on sugar, etc. , and comes out like cockroaches, at night, shunning the light. Like the cockroaches, which it vaguely resembles inform, this species loves hot and dry localities, in distinction from theothers which seek moisture as well as darkness. By some they are called"silver witches, " and as they dart off, when disturbed, like a streak oflight, their bodies being coated in a suit of shining mail, which thearrangement of the scales resembles, they have really a weird andghostly look. 

The most complicated genus, and the one which stands at the head of thefamily, is Machilis, one species of which lives in the Northern andMiddle States, and another in Oregon. They affect damp places, livingunder leaves and stones. They all have rounded, highly arched bodies, and large compound eyes, the two being united together. The maxillarypalpi are greatly developed, but the chief characteristics are thetwo-jointed stylets arranged in nine pairs along each side of theabdomen, reminding us of the abdominal legs of Myriopods. The body endsin three long bristles, as in Lepisma. 

The Lepisma saccharina of Linnæus, if, as is probable, that is the nameof our common species, is not uncommon in old damp houses, where it hasthe habits of the cockroach, eating cloths, tapestry, silken trimmingsof furniture, and doing occasional damage to libraries by devouring thepaste, and eating holes in the leaves and covers of books. 

In general form Lepisma may be compared to the larva of Perla, anet-veined Neuropterous insect, and also to the narrow-bodied species ofcockroaches, minus the wings. The body is long and narrow, covered withrather coarse scales, and ends in three many jointed anal stylets, orbristles, which closely resemble the many jointed antennæ, which areremarkably long and slender. The thermophilous species already alludedto may be described as perhaps the type of the genus, the L. Saccharinabeing simpler in its structure. The body is narrow and flattened; thebasal joints of the legs being broad, flat and almost triangular, likethe same joints in the cockroaches. The legs consist of six joints, thetarsal joints being large and two in number, and bearing a pair ofterminal curved claws. The three thoracic segments are of nearly equalsize, and the eight abdominal segments are also of similar size. Thetracheæ are well developed, and may be readily seen in the legs. The endof the rather long and weak abdomen is propped up by two or three pairsof bristles, which are simple, not jointed, but moving freely at theirinsertion; thus they take the place of legs, and remind one of theabdominal legs of the Myriopods; and we shall see in certain othergenera (Machilis and Campodea) of the Bristle-tails that there areactually two-jointed bristles arranged in pairs along the abdomen. Theymay probably be directly compared with the abdominal legs of Myriopods. Further study, however, of the homologies of these peculiar appendages, and especially a knowledge of the embryological development of Lepismaand Machilis, is needed before this interesting point can be definitelysettled. The three many jointed anal stylets may, however, be directlycompared with the similar appendages of Perla and Ephemera. The mode ofinsertion of the antennæ of this family is much like that of theMyriopods, the front of the head being flattened, and concealing thebase of the antennæ, as in the Centipedes and Pauropus. Indeed, the headof any Thysanurous insect seen from above, bears a general resemblancein some of its features to that of the Centipede and its allies. So in aless degree does the head of the larvæ of certain Neuroptera andColeoptera. The eyes are compound, the single facets forming a sort ofheap. The clypeus and labrum, or upper lip, is, in all the Thysanura, carried far down on the under side of the head, the clypeus being almostobsolete in the Poduridæ, this being one of the most essentialcharacters of that family. Indeed, it is somewhat singular that theseand other important characteristics of this group have been almostentirely passed over by authors, who have consequently separated theseinsects from other groups on what appear to the writer as comparativelyslight and inconsiderable characters. The mouth-parts of the Lepismatidæ(especially the thermophilous Lepisma, which we now describe) are mostreadily compared with those of the larva of Perla. The rather large, stout mandibles are concealed at their tips, under the upper lip, whichmoves freely up and down when the creature opens its mouth. The mandibleis about one-third as broad as long, armed with three sharp teeth on theouter edge, and with a broad cutting edge within, and still furtherinwards a lot of straggling spinules. In all these particulars, themandible of Lepisma is comparable with that of certain Coleoptera andNeuroptera. So also are the maxillæ and labium, though we are not awarethat any one has indicated how close the homology is. The accompanyingfigure (152) of the maxilla of a beetle may serve as an example of themaxilla of the Coleoptera, Orthoptera and Neuroptera. In these insectsit consists almost invariably of three lobes, the outer being thepalpus, the middle lobe the galea, and the innermost the lacinia; thelatter undergoing the greatest modifications, forming a comb composed ofspines and hairs varying greatly in relative size and length. How muchthe palpi vary in these groups of insects is well known. The galeasometimes forms a palpus-like appendage. Now these three lobes may beeasily distinguished in the maxilla of Lepisma. The palpus instead ofbeing directed forward, as in the insects mentioned above (in the pupaof Ephemera the maxilla is much like that of Lepisma), is insertednearer the base than usual and thrown off at right angles to themaxilla, so that it is stretched out like a leg, and in moving about theinsect uses its maxillæ partly as supports for its head. They are verylong and large, and five or six-jointed. The galea, or middle division, forms a simple lobe, while the lacinia has two large chitinous teeth onthe inner edge, and internally four or five hairs arising from a thinedge. 

[Illustration: 152. Maxilla. ]

The labium is much as in that of Perla, being broad and short, with adistinct median suture, indicating its former separation in embryoniclife into a pair of appendages. The labial palpi are three-jointed, thejoints being broad, and in life directed backwards instead of forwardsas in the higher insects. 

There are five American species of the genus Lepisma in the Museum ofthe Peabody Academy. Besides the common L. Saccharina? there are fourundescribed species; one found about out-houses and cellars, and theheat-loving form, perhaps an imported, species, found in a kitchen inSalem, and apparently allied to the L. Thermophila Lucas, of houses inBrest, France; and lastly two allied forms, one from Key West, andanother from Polvon, Western Nicaragua, collected by Mr. McNiel. Thelast three species are beautifully ornamented with finely spinulatedhairs arranged in tufts on the head; while the sides of the body, andedges of the basal joints of the legs are fringed with them. 

The interesting genus Nicoletia stands at the bottom of the group. Ithas the long, linear, scaleless body of Campodea, in the family below, but the head and its appendages are like Lepisma, the maxillary palpibeing five-jointed, and the labial palpi four-jointed. The eyes aresimple, arranged in a row of seven on each side of the head. The abdomenends in three long and many jointed stylets, and there are the usual"false branchial feet" along each side of the abdomen. There are twoEuropean species which occur in greenhouses. No species have yet beenfound in America. 

[Illustration: 153. Japyx solifugus. ]

The next family of Thysanura is the Campodeæ, comprising the two generaCampodea and Japyx. These insects are much smaller than the Lepismidæ, and in some respects are intermediate between that family and thePoduridæ (including the Smynthuridæ). 

In this family the body is long and slender, and the segments much alikein size. There is a pair of spiracles on each thoracic ring. Themandibles are long and slender, ending in three or four teeth, and withthe other appendages of the mouth are concealed within the head, "onlythe tips of the palpi (and of the maxillæ when these are opened)projecting a very little beyond the rounded entire margin of theepistoma, " according to Haliday. The maxillæ are comb-shaped, due to thefour slender, minutely ciliated spines placed within the outer tooth. The labium in Japyx is four-lobed and bears a small two-jointed palpus. The legs are five-jointed, the tarsi consisting of a single joint, ending in two large claws. The abdomen consists of ten segments, and inCampodea along each side is a series of minute, two-jointed appendagessuch as have been described in Machilis. These are wanting in Japyx. None of the species in this family have the body covered with scales. They are white, with a yellowish tinge. 

The more complicated genus of the two is Japyx (Fig. 153, Japyxsolifugus, found under stones in Southern Europe; _a_, the mouth frombeneath, with the maxillæ open; _b_, maxilla; _d_, mandible; _c_, outline of front of head seen from beneath, with the labial palpi inposition) which, as remarked by the late Mr. Haliday (who has publishedan elaborate essay on this genus in the Linnæan Transactions, vol. 24, 1864), resembles Forficula in the large forceps attached to its tail. AnAmerican species (J. Saussurii) lives in Mexico, and we look for itsdiscovery in Texas. 

[Illustration: 154. Campodea staphylinus. ]

Campodea (C. Staphylinus Westw. , Fig. 154, enlarged; _a_, mandible; _b_, maxilla), otherwise closely related, has more rudimentary mouth-parts, and the abdomen ends in two many jointed appendages. 

[Illustration: Fig. 155. Larva of Perla. ]

Our common American species of Campodea (C. Americana) lives understones in damp places. It is yellowish, about a sixth of an inch inlength, is very agile in its movements, and would easily be mistaken fora very young Lithobius. A larger species and differing in having longerantennæ, has been found by Mr. C. Cooke in Mammoth Cave, and has beendescribed in the "American Naturalist" under the name of CampodeaCookei. Haliday has remarked that this family bears much resemblance tothe Neuropterous larva of Perla (Fig. 155), as previously remarked byGervais; and the many points of resemblance of this family and theLepismidæ to the larval forms of some Neuroptera that are active in thepupa state (the Pseudoneuroptera of Erichson and other authors) are verystriking. Campodea resembles the earliest larval form of Chloëon, asfigured by Sir John Lubbock, even to the single jointed tarsus; and whythese two Thysanurous families should be removed from the Neuroptera weare unable, at present, to understand, as to our mind they scarcelydiverge from the Neuropterous type more than the Mallophaga, or bitinglice, from the type of Hemiptera. 

Haliday, remarking on the opinion of Linnæus and Schrank, who referredCampodea to the old genus Podura, says with much truth, "it may beperhaps no unfair inference to draw, that the insect in question is insome measure intermediate between both, " _i. E. _, Podura and Lepisma. This is seen especially in the mouth-parts which are withdrawn into thehead, and become very rudimentary, affording a gradual passage into themouth-parts of the Poduridæ, which we now describe. 

The next group, the Podurelles of Nicolet, and Collembola of Lubbock, are considered by the latter, who has studied them with far more carethan any one else, as "less closely allied" to the Lepismidæ "than hashitherto been supposed. " He says "the presence of tracheæ, the structureof the mouth and the abdominal appendage; all indicate a widedistinction between the Lepismidæ and the Poduridæ. We must, indeed, inmy opinion, separate them entirely from one another; and I wouldventure to propose for the group comprised in the old genus Podura, theterm Collembola, as indicating the existence of a projection, ormammilla, enabling the creature to attach or glue itself to the body onwhich it stands. " Then without expressing his views as to the positionand affinities of the Lepismidæ, he remarks "as the upshot of all this, then, while the Collembola are clearly more nearly allied to the Insectathan to the Crustacea or Arachnida, we cannot, I think, regard them asOrthoptera or Neuroptera, or even as true insects. That is to say, theColeoptera, Orthoptera, Neuroptera, Lepidoptera, etc. , are in myopinion, more nearly allied to one another than they are to the Poduridæor Smynthuridæ. On the other hand, we certainly cannot regard theCollembola as a group equivalent in value to the Insecta. If, then, weattempt to map out the Articulata, we must, I think, regard theCrustacea and Insecta as continents, the Myriopoda and Collembola asislands--of less importance, but still detached. Or, if we represent thedivisions of the Articulata like the branching of a tree, we mustpicture the Collembola as a separate branch, though a small one, andmuch more closely connected with the Insecta than with the Crustacea orthe Arachnida. " Lamarck regarded them as more nearly allied to theCrustacea than Insecta. Gervais, also, in the "Histoire Naturelle desInsectes: Aptères, " indicates a considerable diversity existing betweenthe Lepismidæ and Poduridæ, though they are placed next to each other. Somewhat similar views have been expressed by so high an authority asProfessor Dana, who, in the "American Journal of Science" (vol. 37, Jan. , 1864), proposed a classification of insects based on the principleof cephalization, and divided the Hexapodous insects into three groups:the first (Ptero-prosthenics, or Ctenopters) comprising the Hymenoptera, Diptera, Aphaniptera (fleas), Lepidoptera, Homoptera, Trichoptera andNeuroptera; the second group (Ptero-metasthenics, or Elytropters)comprising the Coleoptera, Hemiptera and Orthoptera; while the Thysanuracompose the third group. Lubbock has given us a convenient historicalview of the opinions of different authors regarding the classificationof these insects, which we find useful. Nicolet, the naturalist who, previous to Lubbock, has given us the most correct and complete accountof the Thysanura, regarded them as an order, equivalent to theColeoptera or Diptera, for example. In this he followed Latreille, whoestablished the order in 1796. The Abbé Bourlet adopted the same view. On the other hand Burmeister placed the Thysanura as a separate tribebetween the Mallophaga (Bird Lice) and Orthoptera, and Gerstaeckerplaced them among the Orthoptera. Fabricius and Blainville put them withthe Neuroptera, and the writer, in his "Guide to the Study of Insects, "and previously in 1863, ignorant of the views of the two last namedauthors, considered the Thysanura as degraded Neuroptera, and noticedtheir resemblance to the larvæ of Perla, Ephemera, and other Neuroptera, such as Rhaphidia and Panorpa, regarding them as standing "in the samerelation to the rest of the Neuroptera [in the Linnæan sense], as theflea does to the rest of the Diptera, or the lice and Thrips to thehigher Hemiptera. "

After having studied the Thysanura enough to recognize the greatdifficulty of deciding as to their affinities and rank, the writer doesnot feel prepared to go so far as Dana and Lubbock, for reasons thatwill be suggested in the following brief account of the more generalpoints in their structure, reserving for another occasion a finalexpression of his views as to their classification. 

The Poduridæ, so well known by name, as affording the scales used bymicroscopists as test objects, are common under stones and wet chips, orin damp places, cellars, mushrooms and about manure heaps. They needmoisture, and consequently shade. They abound most in spring and autumn, laying their eggs at both seasons, though most commonly in the spring. During a mild December, they may be found in abundance under sticks andstones, even in situations so far north as Salem, Mass. 

[Illustration: 156. Smynthurus. ]

The body of the Poduras is rather short and thick, most so in Smynthurus(Fig. 156), and becoming long and slender in Tomocerus and Isotoma. Thesegments are inclined to be of unequal size, the prothoracic ringsometimes becoming almost obsolete, and some of the abdominal rings aremuch smaller than others; while in Lipura and Anura, the lowest forms ofthe group, the segments are all much alike in size. 

The head is in form much like that of certain larvæ of Neuroptera and ofForficula, an Orthopterous insect. The basal half of the head is markedoff from the eye-bearing piece (epicranium) by a V-shaped suture[10](Fig. 157, head of Degeeria; compare also the head of the larva ofForficula, Fig. 158, in which the suture is the same), and the insertionof the antennæ is removed far down the front, near the mouth, theclypeus being very short; this piece, so large and prominent in thehigher insects, is not distinctly separated by suture from thesurrounding parts of the head, thus affording one of the bestdistinctive characters of the Poduridæ. The eyes are situated on top ofthe head just behind the antennæ, and are simple, consisting of a groupof from five to eight or ten united into a mass in Smynthurus, butseparated in the Poduridæ (see Fig. 176, _e_, eye of Anurida). Theantennæ are usually four-jointed, and vary in length in the differentgenera. 

[Illustration: 157. Head of Degeeria. ]

[Illustration: 158. Larva of Forficula. ]

The mouth-parts are very difficult to make out, but by soaking theinsect in potash for twenty-four hours, thus rendering the bodytransparent, they can be satisfactorily observed. They are constructedon the same general type as the mouth-parts of the Neuroptera, Orthoptera and Coleoptera, and except in being degraded, and withcertain parts obsolete, they do not essentially differ. [11] On observingthe living Podura, the mouth seems a simple ring, with a minute labrumand groups of hairs and spinules, which the observer, partly byguess-work, can identify as jaws and maxillæ, and labium. But instudying the parts rendered transparent, we can identify the differentappendages. Figure 159 shows the common Tomocerus plumbeus greatlyenlarged (Fig. 160, seen from above), and as the mouth-parts of thewhole group of Poduras are remarkably constant, a description of onegenus will suffice for all. The labrum, or upper lip, is separated by adeep suture from the clypeus, and is trapezoidal in form. The mandiblesand maxillæ are long and slender, and buried in the head, with the tipscapable of being extended out from the ring surrounding the mouth for avery short distance. The mandibles (_md_, Fig. 159) are like those ofthe Neuroptera, Orthoptera and Coleoptera in their general form, the tipending in from three to six teeth (three on one mandible and six on theother), while below, is a rough, denticulated molar surface, where thefood seized by the terminal teeth is triturated and prepared to beswallowed. Just behind the mandibles are the maxillæ, which aretrilobate at the end, as in the three orders of insects above named. Theouter lobe, or palpus, is a minute membranous tubercle ending in a hair(Fig. 161, _mp_), while the middle lobe, or galea, is nearly obsolete, though I think I have seen it in Smynthurus, where it forms a lobe onthe outside of the lacinia. The lacinia, or inner lobe (Fig. 161, _lc_;162, the same enlarged), in Tomocerus consists of two bundles ofspinules, one broad like a ruffle, and the other slender, pencil-like, ending in an inner row of spines, like the spinules on the lacinia ofthe Japyx and Campodea and, more remotely, the laciniæ of the threesub-orders of insects above referred to. There is also a horny, prominent, three-toothed portion (Fig. 161, _g_). These homologies havenever been made before, so far as the writer is aware, but they seemnatural, and suggested by a careful examination and comparison with theabove-mentioned mandibulate insects. 

[Illustration: 159. 161. 160. 162. 

Tomocerus plumbeus and mouth-parts, greatly enlarged. ]

The spring consists of a pair of three-jointed appendages, with thebasal joints soldered together early in embryonic life, while the othertwo joints are free, forming a fork. It is longest in Smynthurus andDegeeria, and shortest in Achorutes (Fig. 172, _b_), where it forms asimple, forked tubercle; and is obsolete in Lipura and Anura, its placebeing indicated by an oval scar. The third joint varies in form, beinghairy, serrate and knife-like in form, as in Tomocerus (Fig. 159, _a_), or minute, with a supplementary tooth, as in Achorutes (Fig. 172, _c_). This spring is in part homologous with the ovipositor of thehigher insects, which originally consists of three pairs of tubercles, each pair arising apparently from the seventh, eighth, and ninth (thelatter the penultimate) segments of the abdomen in the Hymenoptera. Thespring of the Podura seems to be the homologue of the third pair ofthese tubercles, and is inserted on the penultimate segment. Thiscomparison I have been able to make from a study of the embryology ofIsotoma. 

[Illustration: 163. Catch holding spring of Achorutes. ]

Another organ, and one which, so far as I am aware, has been overlookedby previous observers, I am disposed to consider as possibly anovipositor. In the genus Achorutes, it may be found in the segment justbefore the spring-bearing segment, and situated on the median line ofthe body. It consists (Fig. 163) of two squarish valves, from betweenwhich projects a pair of minute tubercles, or blades, with four roundedteeth on the under side. This pair of infinitesimal saws reminds one ofthe blades of the saw-fly, and I am at a loss what their use can beunless to cut and pierce so as to scoop out a shallow place in which todeposit an egg. It is homologous in situation with the middle pair ofblades which composes the ovipositor of higher insects, and if it shouldprove to be used by the creature in laying its eggs, we should thenhave, with the spring, an additional point of resemblance to theNeuroptera and higher insects, and instead of this spring being animportant differential character, separating the Thysanura from otherinsects, it binds them still closer, though still differing greatly inrepresenting only a part of the ovipositor of the higher insects. (Thisis a catch for holding the spring in place. )

But all the Poduras differ from other insects in possessing a remarkableorgan situated on the basal segment of the abdomen. It is a smalltubercle, with chitinous walls, forming two valves from between which isforced out a fleshy sucker, or, as in Smynthurus, a pair of long tubes, which are capable of being darted out on each side of the body, enablingthe insect to attach itself to smooth surfaces, and rest in an invertedposition. 

The eggs are laid few in number, either singly or several together, onthe under side of stones, chips or, as in the case of Isotoma Walkerii, under the bark of trees. They are round, transparent. The development ofthe embryo of Isotoma in general accords with that of the Phryganeidæand suggests on embryological grounds the near relationship of theThysanura to the Neuroptera. 

[Illustration: 164. 165. 166. 167. 

Development of a Poduran. ]

The earliest stage observed was at the time of the appearance of theprimitive band (Fig. 164, _a_, _b_, folding of the primitive band; _c_, the dotted line crosses the primitive band, and terminates in a largeyolk granule) which surrounds the egg as in the Caddis flies. Soonafter, the primitive segments appear (Fig. 165; 1, antennæ; 2, mandibles; 3, maxillæ; the labium was not seen; 5-7, legs; _c_, yolksurrounded by the primitive band) and seem to originate just as in theCaddis flies. Figure 166 is a front view of the embryo shortly beforeit is hatched; figure 167, side view of the same, the figures as in Fig. 165; _sp_, spring; _l_, labrum. The labrum or upper lip, and the clypeusare large and as distinct as in the embryos of other insects, a fact towhich we shall allude again. The large three-jointed spring is now welldeveloped, and the inference is drawn that it represents a pair of trueabdominal legs. The embryo when about to hatch throws off the egg-shelland amnion in a few seconds. The larva is perfectly white and is veryactive in its movements, running over the damp, inner surface of thebark. It is a little over a hundredth of an inch in length, and differsfrom the adult in being shorter and thicker, with the spring very shortand stout. In fact the larva assumes the form of the lower genera of thefamily, such as Achorutes and Lipura, the adult more closely resemblingDegeeria. The larva after its first moult retains its early clumsy form, and is still white. After a second moult it becomes purplish, and muchmore slender, as in the adult. The eggs are laid and the young hatchedapparently within a period of from six to ten days. 

Returning to the stage indicated by figures 166 and 167, I am induced toquote some remarks published in the Memoirs of the Peabody Academy ofScience, No. 2, p. 18, which seem to support the view that these insectsare offshoots from the Neuroptera. 

"The front of the head is so entirely different from what it is in theadult, that certain points demand our attention. It is evident that atthis period the development of the insect has gone on in all importantparticulars much as in other insects, especially the NeuropterousMystacides as described by Zaddach. The head is longer vertically thanhorizontally, the frontal, or clypeal region is broad, and greater inextent than the epicranio-occipital region. The antennæ are insertedhigh up on the head, next the ocelli, falling down over the clypealregion. The clypeus, however, is merged with the epicranium, and theusual suture between them does not appear distinctly in after life, though its place is seen in figure 167 to be indicated by a slightindentation. The labrum is distinctly defined by a well marked suture, and forms a squarish, knob-like protuberance, and in size is quite largecompared to the clypeus. From this time begins the process ofdegradation, when the insect assumes its Thysanurous characters, whichconsist in an approach to the form of the Myriopodous head, the front, or clypeal region being reduced to a minimum, and the antennæ and eyesbrought in closer proximity to the mouth than in any other insects. "

Sir John Lubbock has given us an admirable account of the internalanatomy of these little creatures, his elaborate and patient dissectionsfilling a great gap in our knowledge of their internal structure. Thespace at our disposal only permits us to speak briefly of therespiratory system. Lubbock found a simple system of tracheæ inSmynthurus which opens by "two spiracles in the head, opposite theinsertion of the antennæ, " _i. E. _, on the back of the head. (Von Olferssays that they open on the prothorax. ) Nicolet and Olfers claim to havefound tracheæ in several lower genera (Orchesella, Tomocerus, andAchorutes and allied genera), but Lubbock was unable to detect them, andI may add that I have not yet been able after careful search to findthem either in living specimens, or those rendered transparent bypotash. 

Having given a hasty sketch of the external aspect of the Poduras, Iextract from Lubbock's work a synopsis of the families and genera forthe convenience of the student, adding the names of known Americanspecies, or indications of undescribed native forms. 

SMYNTHURIDÆ. --Body globular or ovoid; thorax and abdomen forming onemass; head vertical or inclined; antennæ of four or eight segments. Eyeseight on each side, on the top of the head. Legs long and slender. Saltatory appendage with a supplementary segment. 

Smynthurus. Antennæ four-jointed, bent at the insertion of the fourth, which is nearly as long as the other three, and appears to consist ofmany small segments. No conspicuous dorsal tubercles. (In this countryFitch has described five species: S. Arvalis, elegans, hortensis, Novæboracensis, and signifer. Figure 156 represents a species found inMaine. )

Dicyrtoma. Antennæ eight-jointed, five before, three after the bend. Twodorsal tubercles on the abdomen. 

Papirius. [12] Antennæ four-jointed, without a well-marked elbow, andwith a short terminal segment offering the appearance of beingmany-jointed. 

PODURIDÆ. --This family comprises those species of the old genus Podura, in which the mouth has mandibles [also maxillæ and a labium], and thebody is elongated, with a more or less developed saltatory appendage atthe posterior extremity. 

Orchesella. Segments of the body unequal in size, more or less thicklyclothed with clubbed hairs. Antennæ long, six-jointed. Eyes six innumber on each side, arranged in the form of an S. (One or two beautifulspecies live about Salem. )

[Illustration: 168. Degeeria. ]

Degeeria. Segments of the body unequal in size, more or less thicklyclothed by clubbed hairs. Antennæ longer than the head and thorax, filiform, four-jointed. Eyes eight in number on each side of the head. (Two species, Degeeria decem-fasciata, Pl. 10, Figs. 2, 3, and D. Purpurascens, Figs. 4, 5, are figured in the "Guide to the Study ofInsects. " Figure 168 represents a species found in Salem, Mass. , closelyallied to the European D. Nivalis. Five species are already known in NewEngland. )

Seira. Body covered with scales. Antennæ four-jointed; terminal segmentnot ringed. Eyes on a dark patch. Thorax not projecting over the head. Abdominal segments unequal. 

Templetonia. Segments of the body subequal, clothed by clubbed hairs, and provided with scales. Antennæ longer than the head and thorax, five-jointed, with a small basal segment, and with the terminal portionringed. 

Isotoma. Four anterior abdominal segments subequal, two posterior onessmall; body clothed with simple hairs and without scales. Antennæfour-jointed, longer than the head; segments subequal. Eyes seven innumber on each side, arranged in the form of an S. (Three species arefound in Massachusetts, one of which (I. Plumbea) is figured on Pl. 10, Figs. 6, 7, of the "Guide to the Study of Insects, " third edition. )

Tomocerus. Abdominal segments unequal, with simple hairs and scales. Antennæ very long, four-jointed, the two terminal segments ringed. Eyesseven in number on each side. (The European T. Plumbea, Podura plumbeaof authors, is our species, and is common. Fig. 160, greatly enlarged, copied from Templeton; Fig. 159, side view, see also Fig. 161, where themouth-parts are greatly enlarged, the lettering being the same, _md_, mandibles; _mx_, maxillæ; _mp_, maxillary palpus; _lb_, labium; _lp_, labial palpus; _lc_, lacinia; _g_, portion ending in three teeth; _l_, lobe of labium; _sp_, ventral sucking disk; the dotted line's passingthrough the body represent the course of the intestine; _b_, end oftibia, showing the tarsus, with the claw, and two accessory spines; _a_, third joint of the spring. Fig. 162, lacinia of maxilla greatlyenlarged. Fig. 169, different forms of scales, showing the greatvariation in size and form, the narrow ones running into a linear form, becoming hairs. The markings are also seen to vary, showing, theirunreliable character as test objects, unless a single scale is kept foruse. )

[Illustration: 169. Scales of Tomocerus. ]

[Illustration: 170. Lepidocyrtus. ]

[Illustration: 171. Scale of Lepidocyrtus. ]

Lepidocyrtus. Abdominal segment unequal, with simple hairs and scales. Antennæ long, four-jointed. Eyes eight in number on each side. (Fig. 170, L. Albinos, an European species, from Hardwicke's "Science Gossip. "Fig. 171, a scale. Two species live in New England. )

Podura. Abdominal segments subequal. Hairs simple, no scales. Antennæfour-jointed, shorter than the head. Eyes eight in number on each side. Saltatory appendage of moderate length. 

[Illustration: 172. Achorutes. ]

Achorutes. Abdominal segments subequal. Antennæ short, four-jointed. Eyes eight in number on each side. Saltatory appendage quite short. 

Figure 172 represents a species of this genus very abundant under thebark of trees, etc. , in New England. It is of a blackish lead color;_a_, end of tibia bearing a tenant hair, with the tarsal joint and largeclaw; _b_, spring; _c_, the third joint of the spring, with the littlespine at the base; figure 163, the supposed ovipositor; _a_, the twoblades spread apart; _b_, side view. The mouth-parts in this genus aremuch as in Tomocerus, the maxillæ ending in a lacinia and palpus. 

[Illustration: 173. Lipura fimetaria. ]

The three remaining genera, Lipura, Anurida and Anura, are placed in the"family" Lipuridæ, which have no spring. Lubbock remarks that "thisfamily contains as yet only two[13] genera, Lipura (Burmeister), inwhich the mouth is composed of the same parts as those in the precedinggenera, and Anura (Gervais), in which the mandibles and maxillædisappear. " Our common white Lipura is the European L. Fimetaria Linn. (Fig. 173, copied from Lubbock). The site of the spring is indicated byan oval scar. 

[Illustration: 174. 176. 175. 

Anurida maritima. ]

Figure 174 represents Anurida maritima found under stones between tidemarks at Nantucket. It is regarded the same as the European species byLubbock, to whom I had sent specimens for comparison. This genus differsin the form of the head from Lipura and also wants the terminal upcurvedspines, while the antennæ are much more pointed. The legs (Fig. 175) endin a large, long, curved claw. On examining specimens soaked in potash, I have found that the mouth-parts of this species (Fig. 176, ) _md_, mandibles; _mx_, maxillæ; _e_, eyes, and a singular accessory group ofsmall cells, are like those of Achorutes, as previously noticed byLaboulbène. The mandibles, like those of other Poduras, end in fromthree to six teeth, and have a broad, many-toothed molar surface below. The maxillæ; end in a tridentate lacinia as usual, though the palpi andgalea I have not yet studied. 

The genus Anura may be readily recognized by the mouth ending in anacutely conical beak, with its end quite free from the head and hangingdown beneath it. The body is short and broad, much tuberculated, whilethe antennæ are short and pointed, and the legs are much shorter than inLipura, not reaching more than a third of their length beyond the body. Our common form occurs under the bark of trees. 

For the reason that I can find no valid characters for separating thesethree genera as a family from the other Poduras, I am inclined to thinkthat they form, by the absence of the spring, only a subdivision(perhaps a subfamily) of the Poduridæ. 

The best way to collect Poduras is, on turning up the stick or stone onthe under side of which they live, to place a vial over them, allowingthem to leap into it; they may be incited to leap by pushing a needleunder the vial. They may also be collected by a bottle with a spongesaturated with ether or chloroform. They may be kept alive for weeks bykeeping moist slips of blotting paper in the vial. In this way I havekept specimens of Degeeria, Tomocerus and Orchesella, from the middle ofDecember till late in January. During this time they occasionallymoulted, and Tomocerus plumbeus, after shedding its skin, ate it withina few hours. Poduras feed ordinarily on vegetable matter, such as deadleaves and growing cryptogamic vegetation. These little creatures can beeasily preserved in a mixture of alcohol and glycerine, or pure alcohol, though without the glycerine the colors fade. 

We have entered more fully in this chapter into the details of structurethan heretofore, too much so, perhaps, for the patience of our readers. But the study of the Poduras possesses the liveliest interest, sincethese lowest of all the six-footed insects may have been among theearliest land animals, and hence to them we may look with more or lesssuccess for the primitive, ancestral forms of insect life. 

FOOTNOTES:

[Footnote 9: Nicolet, in the "Annales de la Societe Entomologique deFrance" (tome v, 1847), has given us the most comprehensive essay on thegroup, though Latreille had previously published an important essay, "Del'Organization Exterieure des Thysanoures" in the "Nouvelles Annales duMuseum d'Histoire Naturelle, Paris, 1832, " which I have not seen. Gervais has also given a useful account of them in the third volume of"Apteres" of Roret's Suite a Buffion, published in 1844. 

The Abbe Bourlet, Templeton, Westwood, and Haliday have publishedimportant papers on the Thysanura; and Meinert, a Danish naturalist, andOlfers, a German anatomist, have published important papers on theanatomy of the group. In this country Say and Fitch have described lessthan a dozen species, and the writer has described two American speciesof Campodea, C. Americana, our common form, and C. Cookei, discovered byMr. C. Cooke in Mammoth Cave, while Humbert has described in a Frenchscientific journal a species of Jupyx (J. Saussurii) from Mexico. ]

[Footnote 10: The direct homology of these parts of the head (theocciput and the epicranium) with Perla, Forficula, etc. , seems to me thebest evidence we could have that the Poduræ are not an independentgroup. In these most fundamental characters they differ widely from theMyriopods. I am not aware that this important relation has beenappreciated by observers. ]

[Footnote 11: As we descend to the soft, tube-like, suctorial (?) mouthof Anura, which is said not to have hard mouth-parts, we see the finalpoint of degradation to which the mouth of the Thysanura is carried. Ithink that this gradual degradation of the mouth-parts in this groupindicates that the appendages in these animals are not formed on anindependent type, intermediate, so to speak, between the mandibulate andhaustellate types, but are simply a modification (through disuse) of themandibulate type as seen in Neuropterous insects. ]

[Footnote 12: Lubbock considers that Papirius should be placed in adistinct family from Smynthurus, because it wants tracheæ. Theirpresence or absence scarcely seems to us to be a family character, asthey are wanting in the Poduridæ, and are not essential to the life ofthese animals, while in other respects Papirius seems to differ butslightly from Smynthurus. ]

[Footnote 13: Dr. Laboulbène has recently, and we think with goodreason, separated Anura maritima from the genus Anura, under the name ofAnurida maritima. ]

CHAPTER XIII. 

HINTS ON THE ANCESTRY OF INSECTS. 

[Illustration: 177. Pentastoma. ]

[Illustration: 178. Centipede. ]

Though our course through the different groups of insects may haveseemed rambling and desultory enough, and pursued with slight referenceto a natural classification of the insects of which we have spoken, yetbeginning with the Hive bee, the highest intelligence in the vast worldof insects, we have gradually, though with many a sudden step, descendedto perhaps the most lowly organized forms among all the insects, theparasitic mites. While the Demodex is probably the humblest in itsorganization of any of the insects we have treated of, there is stillanother mite, which, some eminent naturalists continue to regard as aworm, which is yet lower in the scale. This is the Pentastoma (Fig. 177, P. Tænioides), which lives in the manner of the tape worm a parasiticlife in the higher animals, though instead of inhabiting the alimentarycanal, the worm-like mite takes up its abode in the nostrils and frontalsinus of dogs and sheep, and sometimes of the horse. At first, however, it is found in the liver or lungs of various animals, sometimes in man. It is then in the earliest or larval state, and assumes its true miteform, being oval in shape, with minute horny jaws adapted for boring, and with two pairs of legs armed with sharp retractile claws. Such ananimal as this is little higher than some worms, and indeed is lowerthan many of them. 

We should also not pass over in silence the Centipedes (Fig. 178, Scolopocryptops sexspinosa) and Galley worms, or Thousand legs and theirallies (Myriopods), which by their long slender bodies, and great numberof segments and feet, vaguely recall the worms. But they, with themites, are true insects, as they are born with only three pairs of feet, as are the mites and ticks, and breathe by tracheæ; and thus a commonplan of structure underlies the entire class of insects. 

[Illustration: 179. Young Pauropus. ]

[Illustration: 180. Spring-tail. ]

[Illustration: 181. Young Julus. ]

A very strange Myriopod has been discovered by Sir John Lubbock inEurope, and we have been fortunate enough to find a species in thiscountry. It is the Pauropus. It consists, when fully grown, of ninesegments, exclusive of the head, bearing nine pairs of feet. The youngof Pauropus (Fig. 179) is born with three pairs of feet, and in itsgeneral appearance reminds us of a spring-tail (Fig. 180) as may be seenby a glance at the cut. This six-legged form of Pauropus may also becompared with the young galley worm (Fig. 181). 

[Illustration: 182. Leptus. ]

[Illustration: 183. Tardigrade. ]

Passing to the group of spiders and mites, we find that the young miteswhen first hatched have but three pairs of feet, while their parentshave four, like the spiders. Figure 182 represents the larva (Leptus)of the red garden mites; while a figure of the "water bear, " orTardigrade (Fig. 183), is introduced to compare with it, as it bears aresemblance to the young of the mites, though their young are born withtheir full complement of legs, an exception to their nearest allies, thetrue mites. Now if we compare these early stages of mites and myriopodswith those of the true six-footed insects, as in the larval Meloë, Cicada, Thrips and Dragon fly, we shall see quite plainly that they allshare a common form. What does this mean? To the systematist whoconcerns himself with the classification of the myriads of differentinsects now living, it is a relief to find that all can be reduced tothe comparatively simple forms sketched above. It is to him a proof ofthe unity of organization pervading the world of insects. He sees hownature, seizing upon this archetypal form has, by simple modificationsof parts here and there, by the addition of wings and other organswanting in these simple creatures, rung numberless changes in thiselemental form. And starting from the simplest kinds, such as thePoduras, Spiders, Grasshoppers and May flies, allied creatures which wenow know were the first to appear in the earlier geologic ages, we riseto the highest, the bees with their complex forms, their diversifiedeconomy and wonderful instincts. In ascending this scale of being, whilethere is a progress upwards, the beetles, for instance, being higherthan the bugs and grasshoppers; and the butterflies and moths, on thewhole, being more highly organized than the flies; and while we see thehymenopterous saw-flies, with their larvæ mimicking so closely thecaterpillars of the butterflies, in the progress from the saw-flies upto the bees we behold a gradual loss of the lower saw-fly characters inthe Cynips and Chalcid flies, and see in the sand-wasps and true waspsa constant and accelerating likeness to the bee form. Yet thiscontinuity of improving organizations is often broken, and we often seeinsects which recall the earlier and more elementary forms. 

[Illustration: 184. Male Stylops. ]

Again, going back of the larval period, and studying the insect in theegg, we find that nearly all the insects yet observed agree moststrikingly in their mode of growth, so that, for instance, the earlierstages of the germ of a bee, fly or beetle, bear a remarkableresemblance to each other, and suggest again, more forcibly than when weexamine the larval condition, that a common design or pattern at firstpervades all. In the light of the studies of Von Baer, of Lamarck andDarwin, should we be content to stop here, or does this ideal archetypebecome endowed with life and have a definite existence, becoming theancestral form of all insects, the prototype which gave birth to thehundreds of thousands of insect forms which are now spread over ourglobe, just as we see daily happens where a single aphis may become theprogenitor of a million offspring clustering on the same tree? Is therenot something more than analogy in the two things, and is not the samelife-giving force that evolves a million young Aphides from the germstock of a single Aphis in a single season, the same in kind with theproduction of the living races of insects from a primeval ancestor? Whenwe see the Aphis giving origin in one season to successive generations, the individuals of which may be counted by the million, it is no lessmysterious than that other succession of forms of insect life which haspeopled the globe during the successive chapters of its history. Whilewe see in one case the origin of individual forms, and cannot explainwhat it is that starts the life in the germ and so unerringly guides thecourse of the growing embryo, it is illogical to deny that the samelife-giving force is concerned in the production of specific and genericforms. 

[Illustration: 185. Female Stylops. ]

Who can explain the origin of the sexes? What is the cause thatdetermines that one individual in a brood of Stylops, for example (Fig. 184, male; Fig. 185, grub-like female in the body of its host), shall bebut a grub, living as a parasite in the body of its host, while itsfellow shall be winged and as free in its actions as the most highlyorganized insect? It is no less mysterious, because it daily occursbefore our eyes. So perhaps none the less mysterious, and no morediscordant with known natural laws may the law that governs the originof species seem to those who come after us. Certainly the presentattempts to discover that law, however fatuitous they may seem to many, are neither illogical, nor, judging by the impetus already given tobiology, or the science of life, labor altogether spent in vain. Thetheory of evolution is a powerful tool, when judiciously used, that musteventually wrest many a secret from the grasp of nature. 

But whether true or unproved, the theory of evolution in some shape hasactually been adopted by the large proportion of naturalists, who findit indispensable in their researches, and it will be used until foundinadequate to explain facts. Notwithstanding the present distrust, andeven fear, with which it is received by many, we doubt not but that incomparatively few years all will acknowledge that the theory ofevolution will be to biology what the nebular hypothesis is to geology, or the atomic theory is to chemistry. While the evolution theory is asyet imperfect, and many objections, some seemingly insuperable, can beraised against it, it should be borne in mind that the nebularhypothesis is still comparatively crude and unsatisfactory, thoughindispensable as a working theory to the geologist; and in chemistry, though the atomic theory may not be satisfactorily demonstrated to someminds until an atom is actually brought to sight, it is yet invaluablein research. 

Many short sighted persons complain that such a theory sets in theback-ground the idea of a personal Creator; but minds no less devout, and perhaps a trifle more thoughtful, see the hand of a Creator not lessin the evolution of plants and animals from prëexistent forms, throughnatural laws, than in the evolution of a summer's shower, through thelaws discovered by the meteorologist, who looks back through myriads ofages to the causes that led to the distribution of mountain chains, ocean currents and trade winds, which combine to produce the necessaryconditions resulting in that shower. 

Indeed, to the student of nature, the evolution theory in biology, withthe nebular hypothesis, and the grand law in physics of the correlationof forces, all interdependent, and revealing to us the mode in which theCreator of the Universe works in the world of matter, together form animmeasurably grander conception of the order of creation and itsOrdainer, than was possible for us to form before these laws werediscovered and put to practical use. We may be allowed, then, in areverent spirit of inquiry, to attempt to trace the ancestry of theinsects, and without arriving, perhaps, at any certain result, for it islargely a matter of speculation, point out certain facts, the thoughtfulconsideration of which may throw light on this difficult andembarrassing question. 

Without much doubt the Poduras are the lowest of the six-footed insects. They are more embryonic in their appearance than others, as seen in thelarge size of the head compared with the rest of the body, the large, clumsy legs, and the equality in the size of the several segmentscomposing the body. In other characters, such as the want of compoundeyes, the absence of wings, the absence of a complete ovipositor, andthe occasional want of tracheæ, they stand at the base of the insectseries. That they are true insects, however, we endeavored to show inthe previous chapter, and that they are neuropterous, we think is mostprobable, since not only in the structure of the insect after birth dothey agree with the larvæ of certain neuropters, but, as we have shownin another place[14] in comparing the development of Isotoma, a Poduran, with that of a species of Caddis fly, the correspondence throughout thedifferent embryological stages, nearly up to the time of hatching, isvery striking. And it is a remarkable fact, as we have previouslynoticed, that when it begins to differ from the Caddis fly embryo, itbegins to assume the Poduran characters, and its developmentconsequently in some degree retrogrades, just as in the lice previous tohatching, as we have shown in a previous chapter, so that I think we arewarranted at present in regarding the Thysanura, and especially thefamily of Podarids as degraded neuropters. Consequently the Poduras didnot have an independent origin and do not, perhaps, represent a distinctbranch of the genealogical tree of articulates. While the Poduras may besaid to form a specialized type, the Bristle-tails (Lepisma, Machilis, Nicoletia and Campodea) are, as we have seen, much more highlyorganized, and form a generalized or comprehensive type. They resemblein their general form the larva of Ephemerids, and perhaps more closelythe immature Perla, and also the wingless cockroaches. 

[Illustration: 186. Embryo of Diplax. ]

[Illustration: 187. Embryo of Louse. ]

Now such forms as these Thysanura, together with the mites and thesingular Pauropus, we cannot avoid suspecting to have been among theearliest to appear upon the earth, and putting together the facts, first, of their low organization; secondly, of their comprehensivestructure, resembling the larvæ of other insects; and thirdly, of theirprobable great antiquity, we naturally look to them as being related inform to what we may conceive to have been the ancestor of the class ofinsects. Not that the animals mentioned above were the actual ancestors, but that certain insects bearing a greater resemblance to them than anyothers with which we are acquainted, and belonging possibly to familiesand orders now extinct, were the prototypes and progenitors of theinsects now known. 

[Illustration: 188. Embryo of Spider. ]

[Illustration: 189. Embryo of Podura. ]

Though the study of the embryology of insects is as yet in its infancy, still with the facts now in our possession we can state with tolerablecertainty that at first the embryos of all insects are remarkably alike, and the process of development is much the same in all, as seen in thefigure of Diplax (Fig. 186), the louse (Fig. 187), the spider (Fig. 188)and the Podura (Fig. 189), and we could give others bearing the samelikeness. We notice that at a certain period in the life of the embryoall agree in having the head large, and bearing from two to four pairsof mouth organs, resembling the legs; the thorax is merged in with theabdomen, and the general form of the embryo is ovate. Now this generalembryonic form characterizes the larva of the mites, of the myriopodsand of the true insects. To such a generalized embryonic form to whichthe insects may be referred as the descendants, we would give the nameof _Leptus_, as among Crustacea the ancestral form is referred toNauplius, a larval form of the lower Crustacea, and through which thegreater part of the Crabs, Shrimps, Barnacles, water fleas, etc. , passto attain their definite adult condition. A little water flea wasdescribed as a separate genus, Nauplius, before it was known to be thelarva of a higher water flea, and so also Leptus was thought to be amature mite. Accordingly, we follow the usage of certain naturalists indealing with the Crustacea, and propose for this common primitive larvalcondition of insects the term Leptus. 

[Illustration: 190. Zoëa. ]

The first to discuss this subject of the ancestry of insects was FritzMüller, who in his "Für Darwin, "[15] published in 1863, says, at the endof his work, "Having reached the Nauplius, the extreme outpost of theclass, retiring farthest into the gray mist of primitive time, wenaturally look round us to see whether ways may not be descried thencetowards other bordering regions. * * * But I can see nothing certain. Even towards the nearer provinces of the Myriopoda and Arachnida I canfind no bridge. For the Insecta alone, the development of theMalacostraca [Crabs, Lobsters, Shrimps, etc. ] may perhaps present apoint of union. Like many Zoëæ, the Insecta possess three pairs of limbsserving for the reception of nourishment, and three pairs serving forlocomotion; like the Zoëæ they have an abdomen without appendages; as inall Zoëæ the mandibles in Insecta are destitute of palpi. Certainly butlittle in common, compared with the much which distinguishes these twoanimal forms. Nevertheless, the supposition that the Insecta had fortheir common ancestor a Zoëa which raised itself into a life on land, may be recommended for further examination" (p. 140). 

Afterwards Hæckel in his "Generelle Morphologie" (1866) and "History ofCreation, " published in 1868, reiterates the notion that the insects arederived from the larva (Zoëa, Fig. 190) of the crabs, though he isdoubtful whether they did not originate directly from the worms. [16]

It may be said in opposition to the view that the insects cameoriginally from the same early crustacean resembling the larva of a crabor shrimp, that the differences between the two types are too great, or, in other words, the homologies of the two classes too remote, [17] andthe two types are each too specialized to lead us to suppose that onewas derived from the other. Moreover, we find through the researches ofMessrs. Hartt and Scudder that there were highly developed insects, suchas May flies, grasshoppers, etc. , in the Devonian rocks of NewBrunswick, leading us to expect the discovery of low insects even in theUpper Silurian rocks. At any rate this discovery pushes back the originof insects beyond a time when there were true Zoëæ, as the shrimps andtheir allies are not actually known to exist so far back as theSilurian, not having as yet been found below the coal measures. 

The view that the insects were derived from a Zoëa was also sustained byFriedrich Brauer, the distinguished entomologist of Vienna, in apaper[18] read in March, 1869. Following the suggestion of Fritz Müllerand Hæckel, he derives the ancestry of insects from the Zoëa of crabsand shrimps. However, he regards the Podurids as the more immediateancestors of the true insects, selecting Campodea as the type of such anancestral form, remarking that the "Campodea-stage has for the Insectsand Myriopods the same value as the Zoëa for the Crustacea. " He saysnothing regarding the spiders and mites. 

At the same time[19] the writer, in criticising Hæckel's views of thederivation of insects from the Crustacea (ignorant of the fact that hehad also suggested that the insects were possibly derived directly fromthe worms, and also independently of Brauer's opinions) declared hisbelief that though it seemed premature, after the discovery of highlyorganized winged insects in rocks so ancient as the Devonian, and withthe late discovery of a land plant in the Lower Silurian rocks ofSweden, [20] to even guess as to the ancestry of insects, yet he wouldsuggest that, instead of being derived from some Zoëa, "the ancestors ofthe insects (including the six-footed insects, spiders and myriopods)must have been worm-like and aquatic, and when the type becameterrestrial we would imagine a form somewhat like the young Pauropus, which combines in a remarkable degree the characters of the myriopodsand the degraded wingless insects, such as the Smynthurus, Podura, etc. Some such forms may have been introduced late in the Silurian period, for the interesting discoveries of fossil insects in the Devonian of NewBrunswick, by Messrs. Hartt and Scudder, and those discovered by Messrs. Meek and Worthen in the lower part of the Coal Measures at Morris, Illinois, and described by Mr. Scudder, reveal carboniferous myriopods(two species of Euphorberia) more highly organized than Pauropus, and acarboniferous scorpion (Buthus?) closely resembling a species now livingin California, together with another scorpion-like animal, MazoniaWoodiana, while the Devonian insects described from St. John by Mr. Scudder, are nearly as highly organized as our grasshoppers and Mayflies. Dr. Dawson has also discovered a well developed milleped(Xylobius) in the Lower Coal Measures of Nova Scotia; so that we must goback to the Silurian period in our search for the earliest ancestor, or(if not of Darwinian proclivities) prototype, of insects. "

Afterwards[21] the writer, carrying out the idea suggested above, "referred the ancestry of the Myriopods, Arachnids, and Hexapodousinsects to a Leptus-like terrestrial animal, bearing a vague resemblanceto the Nauplius form among Crustacea, inasmuch as the body is notdifferentiated into a head, thorax and abdomen [though the head may befree from the rest of the body] and there are three pairs of temporarylocomotive appendages. Like Nauplius, which was first supposed to be anadult Entomostracan, the larval form of Trombidium had been described asa genus of mites under the name of Leptus (also Ocypete and Astoma) andwas supposed to be adult. "

In the same year Sir John Lubbock[22] agrees with Brauer that the groupsrepresented by Podura and Campodea may have been the ancestors of theinsects, remarking that "the genus Campodea must be regarded as a formof remarkable interest, since it is the living representative of aprimæval type from which not only the Collembola (Podura, etc. ) andThysanura, but the other great orders of insects, have all derived theirorigin. "

The comparison of the Leptus with the Nauplius, or pre-Zoëal stage ofCrustacea, is much more natural. But here we are met with apparentlyinsuperable difficulties. While the Nauplius (Fig. 191) has but threepairs of appendages, which become the two pairs of antennæ andsucceeding pair of limbs of the adult, in the Leptus as the least numberwe have five pairs, two of which belong to the head (the maxillæ andmandibles) and three to the thorax; besides these is a true heed, distinct from the hinder region of the body. It is evident that theLeptus fundamentally differs from the Nauplius and begins life on ahigher plane. We reject, therefore, the Crustacean origin of theinsects. Our only refuge is in the worms, and how to account for thetransmutation of any worm with which we are at present acquainted into aform like the Leptus, with its mandibulated mouth and jointed legs, seems at first well nigh impossible. We have the faintest possibleindication in the structure of some mites, and of the Tardigrades andPentastoma, where there is a striking recurrence, as we may term it, toa worm-like form, readily noticed by every observer, whatever hisopinion may be on the developmental theory. In the Demodex we see atendency of the mite to assume under peculiar circumstances anelongated, worm-like form. The mouth-parts are aborted (though from whatwe know of the embryology of other mites, they probably are indicatedearly in embryonic life), while the eight legs are not jointed, and formsimple tubercles. In the Tardigrades, a long step lower, we haveunjointed fleshy legs armed with from two to four claws, but themouth-parts are essentially mite in character. A decided worm feature isthe fact that they are hermaphrodites, each individual having ovariesand spermaries, as is the case with many worms. 

[Illustration: 191. Nauplius. ]

When we come to the singular creatures of which Pentastoma andLinguatula are the type, we have the most striking approximation to theworms in external form, but these are induced evidently by theirparasitic mode of life. They lose the rudimentary jointed limbs whichsome (Linguatula especially) have well marked in the embryo, and frombeing oval, rudely mite-like in form, they elongate, and only the clawsor simple curved hooks, like those of young tape worms, remain toindicate the original presence of true jointed legs. 

In seeking for the ancestry of our hypothetical Leptus among the worms, we are at best groping in the dark. We know of no ancestral form amongthe true Annelides, nor is it probable that it was derived from theintestinal worms. The only worm below the true Annelides that suggestsany remote analogy to the insects is the singular and rare Peripatus, which lives on land in warm climates. Its body, not divided into rings, is provided with about thirty pairs of fleshy tubercles, each ending intwo strong claws, and the head is adorned with a pair of fleshytubercles. It is remotely possible that some Silurian land worm, if anysuch existed, allied to our living Peripatus, may have been the ancestorof a series of types now lost which resulted in an animal resembling theLeptus. 

[Illustration: 192. Platygaster error. ]

We may, however, as bearing upon this difficult question, cite someremarkable discoveries of Professor Ganin, a Russian naturalist, on theearly stages of certain ichneumon parasites, which show some wormfeatures in their embryonic development. In a species of Platygaster(Fig. 192, P. Error of Fitch), which is a parasite on a two-winged gallfly, the earliest stage observed after the egg is laid is that in whichthe egg contains a single cell with a nucleus and nucleolus. Out of thiscell (Fig. 193 _A_, _a_) arise two other cells. The central cell (_a_)gives origin to the embryo. The two outer ones multiply by subdivisionand form the embryonal membrane, or "amnion, " which is a provisionalenvelope and does not assist in building up the body of the germ. Thecentral single cell, however, multiplies by the subdivision of itsnucleus, thus building up the body of the germ. Figure 193 _B_, _g_, shows the yolk or germ just forming out of the nuclei (_a_) and _b_, theperipheral cells of the blastoderm skin, or "amnion. " Figure 193 _C_shows the yolk transformed into the embryo (_g_), with the outer layerof blastodermic cells (_b_). The body of the germ is infolded, so thatthe embryo appears bent on itself. Figure 193 _D_ shows the embryo muchfarther advanced, with the two pairs of lobes (_md_, rudimentarymandibles; _d_, rudimentary pad-like organs, seen in a more advancedstage in _E_), and the bilobate tail (_st_). Figure 194 (_m_, mouth;_at_, rudimentary antennæ; _md_, mandibles; _d_, tongue-like appendages;_st_, anal stylets; the subject of this figure is of a different speciesfrom the insect previously figured, which, however, it closelyresembles) shows the first larva stage after leaving the egg. Thisstrange form, the author remarks, would scarcely be thought an insect, were not its origin and farther development known, but rather aparasitic Copepodous crustacean, whence he calls this the Cyclops-likestage. In this condition it clings to the inside of itshost by means of its hook-like jaws (_md_), moving about like a Cestodesembryo with its well known six hooks. The tail moves up and down, and isof but little assistance in its efforts to change its place. Singularlyenough, the nervous, vascular, and respiratory systems (tracheæ) arewanting, and the alimentary canal is a blind sac, remaining in anindifferent, or unorganized state. How long it remains in this statecould not be ascertained. 

[Illustration: 193. Development of Platygaster. ]

[Illustration: 194. First Larva of Platygaster. ]

[Illustration: 195. Second Larva of Platygaster. ]

The second larval stage (Fig. 195; _oe_, oesophagus; _ng_, supra-oesophageal ganglion; _n_, nervous cord; _ga_, and _g_, genitalorgans; _ms_, band of muscles) is attained by means of a moult, as usualin the metamorphoses of insects. With the change of skin the larvaentirely changes its form. So-called hypodermic cells are developed. Thesingular tail is dropped, the segments of the body disappear, and thebody grows oval, while within begins a series of remarkable changes, like the ordinary development of the embryo of most other insects withinthe egg. The cells of the hypodermis multiply greatly, and lie one abovethe other in numerous layers. They give rise to a special primitiveorgan closely resembling the "primitive band" of all insect embryos. Thealimentary canal is made anew, and the nervous and vascular systems nowappear, but the tracheæ are not yet formed. It remains in this state fora much longer period than in the previous stage. 

[Illustration: 196. Third Larva of Polynema. ]

The third larval form only a few live to reach. This is of the usuallong, oval form of the larvæ of the ichneumons, and the body hasthirteen segments exclusive of the head. The muscular system has greatlydeveloped and the larva is much more lively in its motions than before. The new organs that develop are the air tubes and fat bodies. The"imaginal disks" or rudimentary portions destined to develop and formthe skin of the adult, or imago, arise in the pupa state, whichresembles that of other ichneumons. These disks are only engaged, inPlatygaster, in building up the rudimentary appendages, while in theflies (Muscidæ and Corethra) they build up the whole body, according tothe remarkable discovery of Weismann. 

Not less interesting is the history of the development of a species ofPolynema, another egg-parasite, which lays its eggs (one, seldom two) inthe eggs of a small dragon fly, Agrion virgo, which oviposits in theparenchyma of the leaves of waterlilies. The eggs develop as inPlatygaster. The earliest stage of the embryo is very remarkable. Itleaves the egg when very small and immovable, and with scarcely a traceof organization, being a mere flask-shaped sac of cells. [23] It remainsin this state five or six days. 

In the second stage, or Histriobdella-like form, the larva is, in itsgeneral appearance, like the low worm to which Ganin compares it. It maybe described as bearing a general resemblance to the third and fullydeveloped larval form (Fig. 196, _tg_, three pairs of abdominaltubercles destined to form the sting; _l_, rudiments of the legs; _fk_, portion of the fatty body; _at_, rudiments of the antennæ; _fl_, imaginal disks, or rudiments of the wings). No tracheæ are developed inthe larva, nor do any exist in the imago. (Ganin thinks, that as theseinsects are somewhat aquatic, the adult insects flying over the surfaceof the water, the wings may act as respiratory organs, like gills. ) Itlives six to seven days before pupating, and remains from ten to twelvedays in the pupa state. 

The origin of the sting is clearly ascertained. Ganin shows that itconsists of three pairs of tubercles, situated respectively on theseventh, eighth, and ninth segments of the abdomen (Fig. 196, _tg_). Thelabium is not developed from a pair of tubercles, as is usual, but atonce appears as an unpaired, or single organ. The pupa state lasts forfive or six days, and when the imago appears it eats its way through asmall round opening in the end of the skin of its host, the Agrionlarva. 

[Illustration: 197. Development of Egg-parasites. ]

The development of Ophloneurus, another egg-parasite, agrees with thatof Platygaster and Polynema. This egg-parasite passes its early life inthe eggs of Pieris brassicæ, and two or three live to reach the imagostate, though about six eggs are deposited by the female. The eggs areoval, and not stalked. The larva is at first of the form indicated byfigure 197 _E_, and when fully grown becomes of a broad oval form, thebody not being divided into segments. It differs from the genera alreadymentioned, in remaining within its egg membrane, and not assuming theirstrange forms. From the non-segmented, sac-like larva, it passesdirectly into the pupa state. 

The last egg-parasite noticed by Ganin, is Teleas, whose developmentresembles that of Platygaster. It is a parasite in the eggs of Gerris, the Water Boatman. Figure 197 _A_ represents the egg; _B_, _C_, and _D_, the first stage of the larva, the abdomen (or posterior division of thebody) being furnished with a series of bristles on each side. (_B_represents the ventral, _C_ the dorsal, and _D_ the profile view; _at_, antennæ; _md_, hook-like mandibles; _mo_, mouth; _b_, bristles; _m_, intestine; _sw_, the tail; _ul_, under lip or labium. ) In the secondlarval stage, which is oval in form, and not segmented, the primitiveband is formed. 

In concluding the account of his remarkable discoveries, Ganin drawsattention to the great differences in the formation of the eggs and thegerms of these parasites from what occurs in other insects. The egg hasno nutritive cells; the formation of the primitive band, usually thefirst indication of the germ, is retarded till the second larval stageis attained; and the embryonal membrane is not homologous with theso-called "amnion" of other insects, but may possibly be compared withthe skin developed on the upper side of the low, worm-like acarian, Pentastomum, and the "larval skin" of the embryos of many low Crustacea. He says, also, that we cannot, perhaps, find the homologues of theprovisional organs of the larvæ, such as the singularly shaped antennæ, the claw-like mandibles, the tongue-or ear-like appendages, in otherArthropoda (insects and Crustacea); but that they may be found in theparasitic Lernæan crustaceans, and in the leeches, such as Histriobella. He is also struck by the similarity in the development of theseegg-parasites to that of a kind of leech (Nephelis), the embryo of whichis provided with ciliæ, recalling the larva of Teleas (Fig. 197 _B_, _C_), while in the true leeches (Hirudo) the primitive band is notdeveloped until after they have passed through a provisional larvalstage. 

This complicated metamorphosis of the egg-parasites, Ganin also comparesto the so-called "hyper-metamorphosis" of certain insects (Meloë, Sitaris, and the Stylopidæ) made known by Siebold, Newport and Fabre, and he considers it to be of the same nature. 

He also, in closing, compares such early larval forms as those given infigures 193 _E_ and 194, to the free swimming Copepoda. Finally, he saysa few words on the theory of evolution, and remarks "there is no doubtthat, if a solution of the questions arising concerning the genealogicalrelations of different animals among themselves is possible, comparativeembryology will afford the first and truest principles. " He modestlysuggests that the facts presented in his paper will widen our views onthe genetic relations of the insects to other animals, and refers to theopinion first expressed by Fritz Müller (Für Darwin, p. 91), andendorsed by Hæckel in his "Generelle Morphologie, " that we must seek forthe ancestors of insects and Arachnida in the Zoëa form of Crustacea. Hecautiously remarks, however, that "the embryos and larvæ observed by mein the egg-parasites open up a new and wide field for a whole series ofsuch considerations; but I will suppress them, since I am firmlyconvinced that a theory, which I build up to-day, can easily bedestroyed with some few facts which I learn to-morrow. Since comparativeembryology as a science does not yet exist, so do I think that allgenetic theories are too premature, and without a strong scientificfoundation. "

The writer is perhaps less cautious, but he cannot refrain from makingsome reflections suggested by the remarkable discoveries of Ganin. Inthe first place, these facts bear strongly on the theory of evolution by"acceleration and retardation. " In the history of these early larvalstages we see a remarkable acceleration in the growth of the embryo. Asimple sac of unorganized cells, with a half-made intestine, so tospeak, is hatched, and made to perform the duty of an ordinary, quitehighly organized larva. Even the formation of the "primitive band, "usually the first indication of the organization of the germ, ispostponed to a comparatively late period in larval life. The differentanatomical systems, _i. E. _, the heart with its vessels, the nervoussystem and the respiratory system (tracheæ), appear at longer or shorterintervals, while in one genus the tracheæ are not developed at all. Thussome portions of the animal are accelerated in their development morethan others, while others are retarded, and in some species certainorgans are not developed at all. Meanwhile all live in a fluid medium, with much the same habits, and surrounded with quite similar physicalconditions. 

The highest degree of acceleration is seen in the reproductive organsof the Cecidomyian larva of Miastor, which produces a summer brood ofyoung, alive, and living free in the body of the child-parent; and inthe pupa of Chironomus, which has been recently shown by Von Grimm, afellow countryman of Ganin, to produce young in the spring, while theadult fly lays eggs in the autumn in the usual manner. This is in fact atrue virgin reproduction, and directly comparable to the alternation ofgenerations observed in the jelly fishes, in Salpa, and certainintestinal worms. We can now, in the light of the researches of Siebold, Leuckart, Ganin and others, trace more closely than ever the connectionbetween simple growth and metamorphosis, and metamorphosis andparthenogenesis, and perceive that they are but the terms of a singleseries. By the acceleration in the development of a single set of organs(the reproductive), no more wonderful than the acceleration andretardation of the other systems of organs, so clearly pointed out inthe embryos of Platygaster and its allies, we see how parthenogenesisunder certain conditions may result. The barren Platygaster larva, thefertile Cecidomyia larva, the fertile Aphis larva, the fertileChironomus pupa, the fertile hydroid polype, and the fertile adult queenbee are simply animals in different degrees of organization, and withreproductive systems differing not in quality, but in the greater orless rapidity of their development as compared with the rest of thebody. 

Another interesting point is, that while the larvæ vary so remarkably inform, the adult ichneumon flies are remarkably similar to one another. Do the differences in their larval history seem to point back to certainstill more divergent ancestral forms?

These remarkable hyper-metamorphoses remind us of the metamorphosis ofthe embryo of Echinoderms into the Pluteus-and Bipinnaria-forms of thestarfish, sea urchins and Holothurians;[24] of the Actinotrocha-formlarva of the Sipunculoid worms; of the Tornaria into Balanoglossus, theworm; of the Cercaria-form larva of Distoma; of the Pilidium-form larvaof Nemertes; and the larval forms of the leeches;[25] as well as themite Pentastomum, and certain other aberrant mites, such as Myobia. 

While Fritz Müller and Dohrn have considered the insects as havingdescended from the Crustacea (some primitive zoëa-form), and Dohrn hasadduced the supposed zoëa-form larva of these egg-parasites as a proof, we cannot but think, in a subject so purely speculative as the ancestryof animals, that the facts brought out by Ganin tend to confirm ourtheory, that the ancestry of all the insects (including the Arachnidsand Myriopods) should be traced directly to the worms. The developmentof the degraded, aberrant Arachnidan Pentastomum accords, in someimportant respects, with that of the intestinal worms. The Leptus-formlarva of Julus, with its strange embryological development, in somerespects so like that of some worms, points in that direction, ascertainly as does the embryological development of the egg-parasiteOphioneurus. The Nauplius form of the embryo or larva of nearly allCrustacea, also points back to the worms as their ancestors, thedivergence having perhaps originated, as we have suggested, in theRotatoria. 

While the Crustacea may have resulted from a series of prototypesleading up from the Rotifers (Fig. 198), it is barely possible that oneof these creatures may have given rise to a form resulting in two seriesof beings, one leading to the Leptus form, the other to the Nauplius. For the true Annelides (Chætopods) are too circumscribed and homogeneousa group to allow us to look to them for the ancestral forms of insects. But that the insects may have descended from some low worms is notimprobable when we reflect that the Syllis and allied genera ofAnnelides bear appendages consisting of numerous joints; indeed, thestrange Dujardinia rotifers, figured by Quatrefages, in its general formis remarkably like the larva of Chloëon. It has a quite distinct head, bearing five long, slender, jointed antennæ, and but eight or nine ringsto the body, which ends in two long, many jointed appendages exactlylike the tentacles. Quatrefages adds, that its movements are usuallyslow, but "when it wishes to move more rapidly, it moves its bodyalternately up and down with much vivacity, and shoots forwards bybounds, so to speak, a little after the manner of the larvæ of themosquito" (Histoire Naturelle des Annelés, Tome 2, p. 69). The gills ofaquatic insects only differ from those of worms in possessing tracheæ, though the gills of the Crustacea may be directly compared with those ofinsects. 

[Illustration: 198. A Rotifer. ]

But when once inside the circle of the class of insects the ground isfirmer, as our knowledge is surer. Granting now that the Leptus-likeancestor of the six-footed insects has become established, it is not sodifficult to see how the Poduræ and finally a form like Campodeaappeared. Aquatic forms resembling the larva of the Ephemeræ, Perlæ and, more remotely, the Forficulæ and white ants of to-day were probablyevolved with comparative suddenness. Given the evolution of forms likethe earwigs (Forficula), cockroaches and white ants (Termes), the latterof which abounded in the coal period, and it was not a great stepforward to the evolution of the Dragonflies, the Psocus, the Chrysopa, the lice or parasitic Hemiptera, together with Thrips, thus forming theestablishment of lines of development leading up to those Neuropterawith a complete metamorphosis, and finally to the grasshoppers and otherforms of Orthoptera, together with the Hemiptera. 

[Illustration: 199. Chrysopa. ]

[Illustration: 200. Panorpa. ]

We have thus advanced from wingless to winged forms, _i. E. _, frominsects without a metamorphosis to those with a partial metamorphosislike the Perlas; to the May flies and Dragon flies, in which the adultis still more unlike the larva; to the Chrysopa (Fig. 199) and ForcepsTails (Panorpa, Fig. 200) and Caddis flies, in which, especially thelatter, the metamorphosis is complete, the pupa being inactive andenclosed in a cocoon. 

[Illustration: 201. Embryo of Diplax. ]

Having assumed the creation of our Leptus by evolutional laws, we mustnow account for the appearance of tracheæ and those organs so dependenton them, the wings, which, by their presence and consequent changes inthe structure of the crust of the body, afford such distinctivecharacters to the flying insects, and raise them so far above thecreeping spiders and centipedes. Our Leptus at first undoubtedlybreathed through the skin, as do most of the Poduras, since we have beenunable to find tracheæ in them, nor even in the prolarva of a genus ofminute ichneumon egg parasites, nor in the Linguatulæ and Tardigrades, and some mites, such as the Itch insect and the Demodex, and otherAcari. In the Myriopod, Pauropus, Lubbock was unable to find any tracesof tracheæ. If we examine the embryo of an insect shortly before birth, as in the young Dragon fly (figure 201, the dotted line _t_ crosses therudimentary tracheæ), we find it to consist of two simple tubes withfew branches, while there are no stigmata, or breathing holes, to beseen in the sides of the body. This fact sustains the view ofGegenbaur[26] that at first the tracheæ formed two simple tubes in thebody-cavity, and that the primary office of these tubes was forlightening the body, and that their function as respiratory tubes was asecondary one. The aquatic Protoleptus, as we may term the ancestor ofLeptus, may have had such tubes as these, which acted like the swimmingbladder of fishes for lightening the body, as suggested by Gegenbaur. Itis known that the swimming bladder of fishes becomes developed into thelungs of air-breathing vertebrates and man himself. As our Leptusadopted a terrestrial life and needed more air, a connection wasprobably formed by a minute branch on each side of the body with someminute pore (for such exist, whose uses are as yet unknown) through theskin, which finally became specialized into a stigma, or breathing pore;and from the tracheal system being closed, we now have the open trachealsystem of land insects. 

The next inquiry is as to the origin of the wings. Here the questionarises if wingless forms are exceptional among the winged insects, andthe loss of wings is obviously dependent on the habits (as in the lice), and environment of the species (as in beetles living on islands, whichare apt to lose the hinder pair of wings), why may not their acquisitionin the first place have been due to external agencies; and, as they aresuddenly discarded, why may they not have suddenly appeared in the firstplace? In aquatic larvæ there are often external gill-like organs, beingsimple sacs permeated by tracheæ (as in Agrion, Fig. 129, or the Mayflies). These organs are virtually aquatic wings, aiding the insect inprogression as well as in aërating the blood, as in the true wings. Theyare very variable in position, some being developed at the extremity ofthe abdomen, as in Agrion, or along the sides, as in the May flies, orfiliform and arranged in tufts on the under side of the body, as inPerla; and the naturalist is not surprised to find them absent orpresent in accordance with the varying habits of the animal. Forexample, in the larvæ of the larger Dragon flies (Libellula, etc. ) theyare wanting, while in Agrion and its allies they are present. 

Now we conceive that wings formed in much the same way, and with no moredisturbance, so to speak, to the insect's organization, appeared duringa certain critical period in the metamorphosis of some early insect. Assoon as this novel mode of locomotion became established we can easilysee how surrounding circumstances would favor their farther developmentuntil the presence of wings became universal. If space permitted us topursue this interesting subject farther, we could show how invariablycorrelated in form and structure are the wings of insects to the variedconditions by which they are surrounded, and which we are forced tobelieve stand in the relation of cause to effect. Again, why should thewings always appear on the thorax and on the upper instead of the underside? As this is the seat of the centre of gravity, it is evident thatcosmical laws as well as the more immediate laws of biology determinethe position and nature of the wings of an insect. 

Correlated with the presence of wings is the wonderful differentiationof the crust, especially of the thorax, where each segment consists of anumber of distinct pieces; while in the spiders and Myriopods thesegments are as simple as in the abdominal segments of the wingedinsect. It is not difficult here to trace a series leading up from thePoduras, in which the segments are like those of spiders, to thewonderful complexity of the parts in the thoracic segments of theLepidoptera and Hymenoptera. 

In his remarks "On the Origin of Insects, "[27] Sir John Lubbock says, "Ifeel great difficulty in conceiving by what natural process an insectwith a suctorial mouth like that of a gnat or butterfly could bedeveloped from a powerfully mandibulate type like the Orthoptera, oreven from the Neuroptera. " Is it not more difficult to account for theorigin of the mouth-parts at all? They are developed as tubercles orfolds in the tegument, and are homologous with the legs. Figure 186shows that the two sorts of limbs are at one time identical in form andrelative position. The thought suggests itself that these long, soft, finger-like appendages may have been derived from the tentacles of thehigher worms, but the grounds for this opinion are uncertain. At anyrate, the earliest form of limb must have been that of a soft tuberclearmed with one, or two, or many terminal claws, as seen in aquaticlarvæ, such as Chironomus (Fig. 202), Ephydra (Fig. 203 _a_, _b_, _c_, pupa) and many others. As the Protoleptus assumed a terrestrial life andneeded to walk, the rudimentary feet would tend to elongate, and inconsequence need the presence of chitine to harden the integument, untilthe habit of walking becoming fixed, the necessity of a jointedstructure arose. After this the different needs of the offspring of suchan insect, with their different modes of taking food, vegetable oranimal, would induce the diverse forms of simple, or raptorial, orleaping or digging limbs. A peculiar use of the anterior members, asseen in grasping the food and conveying it to the mouth (perhapsoriginally a simple orifice with soft lips, as in Peripatus), would tendto cause such limbs to be grouped together, to concentrate around themouth-opening, and to be directed constantly forwards. With use, as inthe case of legs, these originally soft mouth-feet would graduallyharden at the extremities, until serviceable in biting, when they wouldbecome jaws and palpi. Given a mouth and limbs surrounding it, and we atonce have a rude head set off from the rest of the body. And in factsuch is the history of the development of these parts in the embryo. Atfirst the head is indicated by the buds forming the rudiments of limbs;the segments to which they are attached do not form a true head untilafter the mouth-parts have attained their jaw-like characters, and it isnot until the insect is about to be hatched, that the head is definitelywalled in. 

[Illustration: 202. Foot of Chironomus. ]

[Illustration: 203. Ephydra. ]

We have arrived, then, at our Leptus, with a head bearing two pairs ofjaws. The spiders and mites do not advance beyond this stage. But in thetrue insects and Myriopods, we have the addition of special senseorgans, the antennæ, and another pair of appendages, the labial palpi. It is evident that in the ancestor of these two groups the first pair ofappendages became early adapted for purely sensory purposes, and werenaturally projected far in advance of the mouth, forming the antennæ. 

Before considering the changes from the mandibulate form of insects tothose with mouth parts adapted for piercing and sucking, we mustendeavor to learn how far it was possible for the caterpillar or maggotto become evolved from the Leptus-like larvæ of the Neuroptera, Orthoptera, Hemiptera and most Coleoptera. I may quote from a previousarticle[28] a few words in relation to two kinds of larvæ most prevalentamong insects. "There are two forms of insectean larvæ which are prettyconstant. One we call _leptiform_, from its general resemblance to thelarvæ of the mites (Leptus). The larvæ of all the Neuroptera, exceptthose of the Phryganeidæ and Panorpidæ (which are cylindrical andresemble caterpillars), are more or less leptiform, _i. E. _, have aflattened or oval body, with large thoracic legs. Such are the larvæ ofthe Orthoptera and Hemiptera, and the Coleoptera (except theCurculionidæ; possibly the Cerambycidæ and Buprestidæ, which approachthe maggot-like form of the larvæ of weevils). On the other hand, takingthe caterpillar or bee larva, with their cylindrical, fleshy bodies, inmost respects typical of larval forms of the Hymenoptera, Lepidopteraand Diptera, as the type of the _cruciform_ larva, etc. * * * The larvæof the earliest insects were probably leptiform, and the cruciformcondition is consequently an acquired one, as suggested by FritzMüller. "[29] It seems that these two sorts of larvæ had also beendistinguished by Dr. Brauer in the article already referred to, withwhich, however, the writer was unacquainted at the time of writing theabove quoted article. The similar views presented may seem to indicatethat they are founded in nature. Dr. Brauer, after remarking that thePodurids seemed to fulfil Hæckel's idea of what were the most primitiveinsects, and noticing how closely they resemble the larvæ of Myriopods, says, "specially interesting are those forms among the Poduridæ whichare described as Campodea and Japyx, since the larvæ of a great numberof insects may be traced back to them"; but he adds, and with this viewwe are unable to agree, "while others, the caterpillar-like forms(Raupenform), resulted from them by a retrograde process, and alsothe still lower maggot-like forms. While on the one hand Campodea, withits abdominal feet, and the larva of Lithobius are related, so on theother the Lepismatidæ, which are very near the Blattariæ, are nearlyrelated to the Myriopods, since their abdominal segments often bearappendages (Machilis). The Campodea-form appears in most of thePseudoneuroptera [Libellulids, Ephemerids, Perlids, Psocids and Termes], Orthoptera, Coleoptera, Neuroptera, perhaps modified in the Strepsiptera[Stylops and Xenos] and Coccidæ in their first stage of development, andindeed in many of these at their first moult. " Farther on he says, "Alarger part of the most highly developed insects assume anotherlarva-form, which appears not only as a later acquisition, throughaccommodation with certain definite relations, but also arises as suchbefore our eyes. The larvæ of butterflies and moths, of saw flies andPanorpæ, show the form most distinctly, and I call this the caterpillarform (Raupenform). That this is not the primitive form, but one lateracquired, we see in the beetles. The larvæ of Meloë and Sitaris in theirfully grown condition possess the caterpillar form, but the new bornlarvæ of these genera show the Campodea form. The last form is lost assoon as the larva begins its parasitic mode of life. * * * The largerpart of the beetles, the Neuroptera in part, the bees and flies (thelast with the most degraded maggot form) possess larvæ of this secondform. " He considers that the caterpillar form is a degraded Campodeaform, the result of its stationary life in plants or in wood. 

[Illustration: Pl 2. EXAMPLES OF LEPTIFORM LARVÆ. 

EXPLANATION OF PLATE 2. Figure 1, different forms of Leptus; 2, Diplax;3, Coccinella larva; 4, Cicada larva; 5, Cicindela larva; 6, Ant Lion;7, Calligrapha larva; 8, Aphis larva; 9, Hemerobius larva; 10, Glyrinualarva; 11, Carabid larva; 12, Meloë larva. ]

[Illustration: Pl 3. EXAMPLES OF ERUCIFORM LARVÆ. 

EXPLANATION OF PLATE 3. Figure 1. Panorpa larva; 2, Phryganea larva; 3, Weevil larva; 4, third larva of Meloë; 5, Chionea larva; 6, Carpet Worm;7, Phora larva; 8, Wheat Caterpillar; 9, Sphinx Caterpillar; 10, Acronycta? larva; 11, Saw Fly larva; 12, Abia Saw Fly larva; 13, Halictus larva; 14, Andrena larva. ]

[Illustration: 204. Tipula Larva. ]

For reasons which we will not pause here to discuss, we have alwaysregarded the eruciform type of larva as the highest. That it is theresult of degradation from the Leptus or Campodea form, we should beunwilling to admit, though the maggots of flies have perhaps retrogradedfrom such forms as the larvæ of the mosquitoes and crane flies(Tipulids, Fig. 204). 

That the cylindrical form of the bee grub and caterpillar is the resultof modification through descent is evident in the caterpillar-like formof the immature Caddis fly (Pl. 3, fig. 2). Here the fundamentalcharacters of the larva are those of the Corydalus and Sialis andPanorpa, types of closely allied groups. The features that remind us ofcaterpillars are superadded, evidently the result of the peculiartube-inhabiting habits of the young Caddis fly. In like manner thecaterpillar-form is probably the result of the leaf-eating life of aprimitive Leptiform larva. In like manner the soft-bodied maggot of theweevil is evidently the result of its living habitually in cavities innuts and fruits. Did the soft, baggy female Stylops live exposed, likeits allies in other families, to an out-of-doors life, its skin wouldinevitably become hard and chitinous. In these and multitudes of othercases the adaptation of the form of the insect to its mode of life isone of cause and effect, and not a bit less wonderful after we know whatinduced the change of form. 

Having endeavored to show that the caterpillar is a later productionthan the young, wingless cockroach, with which geological factsharmonize, we have next to account for the origin of a metamorphosis ininsects. Here it is necessary to disabuse the reader's mind of theprevalent belief that the terms larva, pupa and imago are fixed andabsolute. If we examine at a certain season the nest of a humble bee, weshall find the occupants in every stage of growth from the egg to thepupa, and even to the perfectly formed bee ready to break out of itslarval cell. So slight are the differences between the different stagesthat it is difficult to say where the larval stage ends and the pupabegins, so also where the pupal state ends and the imago begins. Thefollowing figures (205-208) will show four of the most characteristicstages of growth, but it should be remembered that there areintermediate stages between. Now we have noticed similar stages in thegrowth of a moth, though a portion of them are concealed beneath thehard, dense chrysalis skin. The external differences between the larvaland pupal states are fixed for a large part of the year in mostbutterflies and moths, though even in this respect there is everypossible variation, some moths or butterflies passing through theirtransformations in a few weeks, others requiring several months, whilestill others take a year, the majority of the moths living under groundin the pupa state for eight or nine months. The stages of metamorphosisin the Diptera are no more suddenly acquired than in the bee orbutterfly. In all these insects the rudiments of the wings, legs, andeven of the ovipositor of the adult exist in the young larva. We havefound somewhat similar intermediate stages in the metamorphoses of thebeetles. The insects we have mentioned are those with a "completemetamorphosis. " We have seen that even in them the term "complete" is arelative and not absolute expression, and that the terms larva and pupaare convenient designations for states varying in duration, and assumedto fulfil certain ends of existence, and even then dependent on lengthof seasons, variation in climate, and even on the locality. When wedescend to the insects with an "incomplete" metamorphosis, as in the Mayfly, we find that, as in the case of Chloëon, Sir John Lubbock hasdescribed twenty-one stages of existence, and let him who can say wherethe larval ends and the pupal or imaginal stages begin. So in a strongersense with the grasshopper and cockroach. The adult state in theseinsects is attained after a number of moults of the skin, during each ofwhich the insect gradually draws nearer to the final winged form. Buteven the so-called pupæ, or half winged individuals known not to beadult, in some cases feel the sexual impulse, while a number of speciesin each of the families represented by these two insects never acquirewings. 

[Illustration: 205. Larva. 206. Semi-pupa. 

207. Advanced Semi-pupa. 208. Pupa. 

EARLY STAGES OF THE HUMBLE BEE. ]

Still how did the perfect metamorphosis arise? We can only answer thisindirectly by pointing to the Panorpa and Caddis flies, with theirnearly perfect metamorphosis, though more nearly allied otherwise tothose Neuroptera with an incomplete metamorphosis, as the lace-wingedfly, than the insects of any other suborder. If, among a group ofinsects such as the Neuroptera, we find different families with allgrades of perfection in metamorphosis, it is possible that larger andhigher groups may exist in which these modes of metamorphosis may befixed and characteristic of each. Had we more space for the expositionof many known facts, the sceptic might perceive that by observing howarbitrary and dependent on the habits of the insects are themetamorphoses of some groups, the fixed modes of other and more generalgroups may be seen to be probably due to biological causes, or in otherwords have been acquired through changes of habits or of the temperatureof the seasons and of climates. Many facts crowd upon us, which mightserve as illustrations and proofs of the position we have taken. Forinstance, though we have in tropics rainy and dry seasons when, in thelatter, insects remain quiescent in the chrysalis state as in thetemperate and frigid zones, yet did not the change from the earlier agesof the globe, when the temperature of the earth was nearly the same theworld over, to the times of the present distribution of heat and cold inzones, possibly have its influence on the metamorphoses of insects andother animals? It is a fact that the remains of those insects with acomplete metamorphosis (the bees, butterflies and moths, flies andbeetles) abound most in the later deposits, while those with anincomplete metamorphosis are fewer in number and the earliest to appear. Again, certain groups of insects are not found in the polar regions. Their absence is evidently due to the adverse climatic conditions ofthose regions. The development of the same groups is striking in thetropics, where the sum of environing conditions all tend to favor themultiplication of insect forms. 

It should be observed that some insects, as the grasshopper, forexample, as Müller says, "quit the egg in a form which is distinguishedfrom that of the adult insect almost solely by the want of wings, " whilethe freshly hatched young of the bee, we may add, is farthest from theform of the adult. It is evident that in the young grasshoppers, themetamorphoses have been passed through, so to speak, in the egg, whilethe bee larva is almost embryonic in its build. The helpless youngmaggot of the wasp, which is fed solely by the parent, may be comparedto the human infant, while the lusty young grasshopper, whichimmediately on hatching takes to the grass or clover field with all theenthusiasm of a duckling to its native pond, may be likened to thatyoung feathered mariner. The lowest animals, as a rule, are at birthmost like the adult. So with the earliest known crustacea. The kingcrabs, and in all probability the primeval trilobites, passed throughtheir metamorphoses chiefly in the egg. So in the ancient Nebaliads(Peltocaris, Discinocaris and Ceratiocaris), if we may follow theanalogy of the recent Nebalia, the young probably closely resembled theadult, while the living crabs and shrimps usually pass through the mostmarked metamorphoses. Among the worms, the highest, and perhaps the mostrecent forms, pass through the most remarkable metamorphoses. 

[Illustration: 209. Jaws of Ant Lion. ]

Another puzzle for the evolutionist to solve is how to account for thechange from the caterpillar with its powerful jaws, to the butterflywith its sucking or haustellate mouth-parts. We shall best approach thesolution of this difficult problem by a study of a wide range of facts, but a few of which can be here noticed. The older entomologists dividedinsects into haustellate or suctorial, and mandibulate or bitinginsects, the butterfly being an example of one, and the beetle servingto illustrate the other category. But we shall find in studying thedifferent groups that these are relative and not absolute terms. We findmandibulate insects with enormous jaws, like the Dytiscus, or Chrysopalarva or ant lion, perforated, as in the former, or enclosing, as in thelatter two insects, the maxillæ (_b_), which slide backward and forwardwithin the hollowed mandibles (_a_, Fig. 209, jaws of the ant lion), along which the blood of their victims flows. They suck the blood, anddo not tear the flesh of their prey. The enormous mandibles of the adultCorydalus are too large for use and, as Walsh observed, are convertedin the male into simple clasping organs. And to omit a number ofinstances, in the suctorial Hemiptera or bugs we have different gradesof structure in the mouth-parts. In the biting lice (Mallophaga) themouth is mandibulate; in the Thrips it is mandibulate, the jaws beingfree, and the maxillæ bearing palpi, while the Pediculi are suctorial, and the true bugs are eminently so. But in the bed bug it is easy to seethat the beak is made up of the two pairs of jaws, which are simplyelongated and adapted for piercing and sucking. Among the so-calledhaustellate insects the mouth-parts vary so much in different groups, and such different organs separately or combined perform the function ofsucking, that the term haustellate loses its significance and evenmisleads the student. For example, in the house fly the tongue (Fig. 210_l_, the mandibles, _m_, and maxillæ, _mp_, are useless), a fleshyprolongation of the labium or second maxillæ, is the sucker, while themandibles and maxillæ are used as lancets by the horse fly (Fig. 211, _m_, mandibles, _mx_, maxillæ). The maxillæ in the butterfly are unitedto form the sucking tube, while in the bee the end of the labium (Fig. 212) is specially adapted for lapping, not sucking, the nectar offlowers. But even in the butterfly, or more especially the moth, thereis a good deal of misapprehension about the structure of the so-called"tongue. " The mouth-parts of the caterpillar exist in the moth. Themandibles of the caterpillar occur in the head of the moth as two smalltubercles (Fig. 213, _m_). They are aborted in the adult. While themaxillæ are as a rule greatly developed in the moth, in the caterpillarthey are minute and almost useless. The labium or second maxillæ, solarge in the moth, serves simply as a spinneret in the caterpillar. Butwe find a great amount of variation in the tongue or sucker of moths, and in the silk moths the maxillæ are rudimentary, and there is notongue, these organs being but little more developed than in thecaterpillar. Figure 213, B, shows the minute blade-like maxilla of themagnificent Luna moth, an approximation to the originally blade-likeform in beetles and Neuroptera. The maxillæ in this insect are minute, rudimentary, and of no service to the creature, which does not takefood. In other moths of the same family we have found the maxillælonger, and touching at their tips, though too widely separate at baseto form a sucking tube, while in others the maxillæ are curved, and meetto form a true tube. 

[Illustration: 210. Mouth-parts of the House fly. ]

[Illustration: 211. Mouth-parts of Horse fly. ]

[Illustration: 212. Head of Humble bee. ]

[Illustration: 213. Mouth-parts of Moths. ]

In the Cecropia moth it is difficult to trace the rudiments of themaxillæ at all, and thus we have in the whole range of the moths, everygradation from the wholly aborted maxillæ of the Platysamia Cecropia, tothose of Macrosila cluentius of Madagascar, which form a tongue, according to Mr. Wallace, nine and a quarter inches in length, probablyto enable their owner to probe the deep nectaries of certain orchids. These changes in form and size are certainly correlated with importantdifferences in habits, and the evolutionist can as rightly say that thestructural changes were induced by use and disuse and change of habitsand the environment of the animal, as on the other hand the advocate ofspecial creation claims that the two are simply correlated, and that isall we know about it. 

[Illustration: 214. Ichneumon Fly. ]

Another set of organs, placed on quite another region of the body, uniteto form the sting of the bee, or its equivalent the ovipositor of otherhymenopterous insects, such as the Ichneumon fly (Fig. 214), the "saw"of the saw fly, and the augur of the Cicada. These are all formed on thesame plan, arising early in the larval stage as three pairs of littletubercles, which ultimately form long blades, the innermost constitutingthe true ovipositor. We have found that one pair of these organs formsthe "spring" of the Podura, and that in these insects it is threejointed, and thus is morphologically a pair of legs soldered together attheir base. We would venture to regard the ovipositor of insects asprobably representing three pairs of abdominal legs, comparable withthose of the Myriopods, and even, as we have suggested in another place, the three pairs of jointed spinnerets of spiders. Thus the ovipositor ofthe bee has a history, and is not apparently a special creation, but astructure gradually developed to subserve the use of a defensive organ. 

So the organs of special sense in insects are in most cases simplyaltered hairs. The hairs themselves are modified epithelial cells. Theeyes of insects, simple and compound, are at first simply epithelialcells, modified for a special purpose, and even the egg is but amodified epithelial cell attached to the walls of the ovary, which inturn is morphologically but a gland. Thus Nature deals in simples, andwith her units of structure elaborates as her crowning work a temple inwhich the mind of man, formed in the image of God, may dwell. Herresults are not the less marvellous because we are beginning to dimlytrace the process by which they arise. It should not lessen our awe andreverence for Deity, if with minds made to adore, we also essay to tracethe movements of His hand in the origin of the forms of life. 

Some writers of the evolution school are strenuous in the belief thatthe evolution hypothesis overthrows the idea of archetypes, and plans ofstructure. But a true genealogy of animals and plants represents anatural system, and the types of animals, be they four, as Cuviertaught, or five, or more, are recognized by naturalists through thestudy of dry, hard, anatomical facts. Accepting, then, the type ofarticulates as founded in nature from the similar modes of developmentand points of structure perceived between the worms and the crustacea onthe one hand, and the worms and insects on the other, have we not astrong genetic bond uniting these three great groups into one grandsubkingdom, and can we not in imagination perceive the successive stepsby which the Creator, acting through the laws of evolution, has built upthe great articulate division of the animal kingdom?

FOOTNOTES:

[Footnote 14: Memoirs of the Peabody Academy of Science, II. Embryological Studies on Diplax, Perithemis, and the Thysanurus genusIsotoma. Salem, 1871. ]

[Footnote 15: Translated in 1859 by Mr. Dallas under the title "Factsfor Darwin. "]

[Footnote 16: "Whether that common stem-form of all the Tracheata[Insects, Myriopods and Spiders] which I have called Protracheata in my'General Morphology' has developed directly from the true Annelides(Coelminthes), or, the next thing to this (_zunachst_), out ofZoea-form Crustacea (Zoepoda), will be hereafter established onlythrough a sufficient knowledge and comparison of the structure and modeof growth of the Tracheata, Crustacea and Annelides. In either case isthe root of the Tracheata, as also of the Crustacea, to be sought in thegroup of the true jointed worms (Annelides, Gephyrea and Rotatoria. " Heconsiders the first insect to have appeared after the Silurian period, viz. , in the Devonian. ]

[Footnote 17: The Zoëa is born with eight pairs of jointed appendagesbelonging to the head, and with no thoracic limbs, while in insectsthere are but four pairs of cephalic appendages and three pairs of legs. Correlated with this difference is the entirely different mode ofgrouping the body segments, the head and thorax being united into oneregion in the crab, but separate in the insects, the body being as arule divided into a head, thorax and abdomen, while these regions aremuch less distinctly marked in the crabs, and liable in the differentorders to great variations. The great differences between the Crustaceaand insects are noticeable at an early period in the egg. ]

[Footnote 18: Considerations on the Transmutation of Insects in theSense of the Theory of Descent. Read before the ImperialZoological-botanical Society in Vienna, April 3, 1869. ]

[Footnote 19: American Naturalist, vol. 3, p. 45, March, 1869. ]

[Footnote 20: See Prof. Torell's discovery of Eophyton Linnæanum, asupposed land plant allied to the rushes and grasses of our day, incertain Swedish rocks of Lower Cambrian age. The writer has, through thekindness of Prof. Torell, seen specimens of these plants in the Museumof the Geological Survey at Stockholm. Mr. Murray, of the CanadianGeological Survey, was the first to discover in America (Labrador, Straits of Belle Isle) this same genus of plants. They are described andfigured by Mr. Billings, who speaks of them as "slender, cylindrical, straight, reed-like plants, " in the "Canadian Naturalist" for August, 1872. 

Should the terrestrial nature of these plants be established on fartherevidence, then we are warranted in supposing that there were isolatedpatches of land in the Cambrian or Primordial period, and if there wasland there must have been bodies of fresh water, hence there may havebeen both terrestrial and aquatic insects, possibly of forms like thePodurids, May flies, Perlæ, mites and Pauropus of the present day. Therewas at any rate land in the Upper Silurian period, as Dr. J. W. Dawsondescribes land plants (Psilophyton) from the Lower Heiderberg Rocks ofGaspe, New Brunswick, corresponding in age with the Ludlow rocks ofEngland. 

We might also state in this connection that Dr. Dawson, the eminentfossil botanist of Montreal, concludes from the immense masses of carbonin the form of graphite in the Laurentian rocks of Canada, that "theLaurentian period was probably an age of most prolific vegetable growth. * * * Whether the vegetation of the Laurentian was wholly aquatic or inpart terrestrial we have no means of knowing. " In 1855, Dr. T. SterryHunt asserted "that the presence of iron ores, not less than that ofgraphite, points to the existence of organic life even during theLaurentian or so-called Azoic period. " In 1861 he went farther andstated his belief in "the existence of an abundant vegetation during theLaurentian period. " The Eophyton in Labrador occurs above the Trilobite(Paradoxides) beds, while in Sweden they occur below. ]

[Footnote 21: In a communication made to the Boston Society of NaturalHistory, Oct. 17, 1870 (see also "American Naturalist" for Feb. AndSept. , 1871). ]

[Footnote 22: On the Origin of Insects, a paper read before the LinnæanSociety of London Nov. 2, 1871, and reported in abstract in "Nature, "Nov. 9, 1871. ]

[Footnote 23: This reminds us (though Ganin does not mention it) of thedevelopment of the embryo of Julus, the Thousand legs, which, accordingto Newport, hatches the 25th day after the egg is laid. At this periodthe embryo is partially organized, having faint traces of segments, andis still enveloped in its embryonal membranes and retains its connectionwith the shell. In this condition it remains for seventeen days, when itthrows off its embryonal membrane, and becomes detached from the shell. ]

[Footnote 24: It is a suggestive fact that these deciduous forms giveway through histolysis to true larval forms, just as in some flies(Musca vomitoria) the true larval form goes under, and the adult form isbuilt up from the imaginal disks of the larva. In an analogous mannerthe deciduous, pluteus-condition of the young Echinoderm perishes and isabsorbed by the growing body of the permanent adult stage. Thisdeciduous stage of the ichneumon may accordingly be termed the prelarvalstage. Now as we find insects with and without this prelarval stage, andin the radiates quite different degrees of metamorphoses, the inquiryarises how far these differences are correlated with, and consequentlydependent upon, the physical surroundings of these animals in the freeswimming condition. Merely to point out the differences in the mode ofdevelopment of animals is an interesting matter, and one could do worsethings, but the philosophical naturalist cannot rest here. He must seekhow these differences were brought about. ]

[Footnote 25: Leuckart, in his great work, "Die Menschlichen Parasiten, "p. 700, after the analogy of Hirudo, which develops a primitive streaklate in larval life, ventures to consider the first indications of thegerm of Nemertes in its larval, Pilidium form as a primitive streak. Healso suggests that the development of the later larval forms of theEchinoderms is the same in kind. 

Moreover, nearly twenty years ago (1854) Zaddach, a German naturalist, contended that the worms are closely allied in their mode of developmentto the insects and crustaceans. He compares the mode of development of aleech (Clepsine) and certain bristle-bearing worms (Sænuris, Lumbricatusand Uaxes); and we may now from Kowalensky's researches (1871) add thecommon earth worm (Lumbricus), in which there is no such metamorphosisas in the sea Nereids, to that of insects; the mode of formation of theprimitive band in the leeches and earth worms being much like that ofinsects. This confirms the view of Leuckart and Ganin, who both seem tohave overlooked Zaddach's remarks. Moreover, the rings of the harderbodied worms, as Zaddach says, contain chitine, as in the insects. Zaddach also enters into farther details, which in his opinion ally theworms nearer to the insects than many naturalists at his time weredisposed to allow. The singular Echinoderes has some remarkableArthropod characters. ]

[Footnote 26: Vergleichende Anatomie, 2te Auflage, 1870, p. 437. Ishould, however, here add that I am told by Mr. Putnam that some fisheswhich have no swim-bladder, are surface-swimmers, and _vice versa_. ]

[Footnote 27: Reported In "Nature" for Nov. 9, 1871. ]

[Footnote 28: The Embryology of Chrysopa, and its bearings on theClassification of the Neuroptera, "American Naturalist, " vol. V. Sept. , 1871. ]

[Footnote 29: "It is my opinion that the 'incomplete metamorphosis' ofthe Orthoptera is the primitive one, _inherited_ from the originalparents of all insects, and the 'complete metamorphosis' of theColeoptera, Diptera, etc. , a subsequently acquired one. " _Fuer Darwin_, English Trans. , p. 121. ]

CHAPTER XIV. 

INSECT CALENDAR. 

In this calendar I propose to especially notice the injurious insects. References to the times of their appearance must be necessarily vague, and apply only, in a very general way, to the Northern States. Insectsappear in Texas about six weeks earlier than in Virginia, in the MiddleStates six weeks earlier than in northern New England and theNorth-western States, and in New England about six weeks earlier than inLabrador. The time of the appearance of insects corresponds to the timeof the flowering or leafing out of certain trees and herbs; forinstance, the larvæ of the American Tent caterpillar and of the Cankerworm hatch just as the apple tree begins to leaf out; a little later thePlant lice appear, to feast on the tender leaves; and when, during thefirst week in June, our forests and orchards are fully leafed out, hostsof insects are marshalled to ravage and devour their foliage. 

_The Insects of Early Spring. _

In April the gardener should scrape and wash thoroughly all his fruittrees, so as to rub off the eggs of the bark lice which hatch out earlyin May. Many injurious caterpillars and insects of all kinds winterunder loose pieces of bark, or under matting and straw at the base ofthe trees. Search should also be made for the eggs of the Canker wormand the American Tent caterpillar, which last are laid in bunches halfan inch long on the terminal shoots of many of our fruit trees. A littlelabor spent in this way will save many dollars' worth of fruit. The"castings" of the Apple Tree Borer (Saperda bivittata) should be lookedfor at the base of the tree, and its ravages be promptly arrested. Itspresence can also be detected, it is said, by the dark appearance of thebark, where the grub is at work: cut in and pull out the young grub. Itis the best time of the year to catch and kill this pest. Cylindricalbark borers, which are little round, black, weevil-like beetles, oftencausing "fire-blight" in pears, etc. , are now flying about fruit treesto lay their eggs; and many other weevils and boring beetles, especiallythe Pea weevil (Bruchus pisi, Fig. 215), the Pine weevil (Pissodesstrobi, Fig. 216), and Hylobius pales and Hylurgus terebrans, alsoinfesting the pine, now abound, and the collector can obtain manyspecimens not met with at other times. 

[Illustration: 215. Pea Weevil and Maggot. ]

[Illustration: 216 Pine Weevil and Young. ]

The housewife must now guard against the intrusion of Clothes moths(Tinea), while many other species of minute moths (Tineids) and ofLeaf-rollers (Tortricidæ) will be flying about orchards and gardens justas the buds are beginning to unfold; especially the Coddling moth(Carpocapsa pomonella). On warm days myriads of these and other insectsmay be seen filling the air; it is the busiest time of their lives, asall are on errands of love to their kind, but of mischief to theagriculturist. 

When the May Flower--"O commendable flowre and most in minde"--blooms, and the willows hang out their golden catkins, we shall hear the hum ofthe wild bee, and the insect hunter will reap a rich harvest ofrarities. Seek now on the abdomen of various wild bees, such as Andrena, for that most eccentric of all our insects, the Stylops Childreni. Thecurious larvæ of the Oil beetle may be found abundantly on the bodies ofvarious species of Bombus, Andrena and Halictus, with their headsplunged in between the segments of the bee's body. 

[Illustration: 217. The Comma Butterfly. ]

[Illustration: 218. Tachina. ]

The beautiful moth, Adela, with its immensely long antennæ, may be seen, with other smaller moths, feeding on the blossoms of the willow. TheAnts wake from their winter's sleep and throw up their hillocks, and the"thriving pismire" issues from his vaulted galleries constructed in somedecaying log or stump, while the Angle worms emulate late theirsix-footed neighbors. During the mild days of March, ere the snow hasmelted away--

 "The dandy Butterfly, All exquisitely drest, "

will visit our gardens. Such are various kinds of Vanessa and Grapta(Fig. 217, G. C-argenteum[30]). The beautiful Brephos infans fliesbefore the snow disappears. 

 "The Gnat, old back-bent fellow, In frugal frieze coat drest, "

will celebrate the coming of Spring, with his choral dance. Such isTrichocera hyemalis, which may be seen in multitudes towards twilight onmild evenings. Many flies are now on the wing, such as Tachina (Fig. 218) and its allies; the four spotted Mosquito, Anophelesquadrimaculatus, and the delicate species of Chironomus, whose maleshave such beautifully feathered antennæ, assemble in swarms. Now is thetime for the collector to turn up stones and sticks by the river's sideand in grassy damp pastures, for Ground beetles (Carabidæ), and tofrequent sunny paths for the gay Cicindela and the Bombylius fly, orfish in brooks and pools for water beetles and various larvæ ofNeuroptera and Diptera; while many flies and beetles are attracted tofreshly cut maples or birches running with sap; indeed, many insects, rarely found elsewhere, assemble in quantities about the stumps of thesetrees, from which the sap oozes in March and April. 

In April the injurious insects in the Northern States have scarcelybegun their work of destruction, as the buds do not unfold before thefirst of May. We give an account, however, of some of the beneficialinsects which are now to be found in grass-lands and in gardens. Thefarmer should know his true insect friends as well as his insect foes. We introduce to our readers a large family of ground-beetles (Carabidæ, from Carabus, the name of the typical genus) which prey on those insectslargely injurious to crops. A study of the figures will familiarize ourreaders with the principal forms. They are dark-colored, brown or black, with metallic hues, and are seen in spring and throughout the summer, running in grass, or lurking under stones and sticks in damp places, whence they sally forth to hunt by night, when many vegetable-eatinginsects are most active. 

[Illustration: 219. Calosoma scrutator. ]

[Illustration: 220. Calosoma calidum and Larva. ]

The larvæ are found in much the same situations as the mature beetles. They are, elongate, oblong, and rather broad, the terminal ring of thebody being armed with two horny hooks, and having a single fleshy legbeneath; and are usually black in color. The larva of Calosoma (C. Calidum, Fig. 220; _a_, the beetle; and Fig. 219, C. Scrutator) ascendstrees to feed on caterpillars, such as the Canker worm. When about totransform to the pupa state, it forms a rude cocoon in the earth. Thebeetle lies in wait for its prey in shallow pits excavated in pastures. We once saw it fiercely attack a May beetle (Lachnosterna fusca) nearlytwice its size; it tore open the hard sides of its clumsy and helplessvictim with tiger-like ferocity. Carabus (Fig. 221, C. Serratus Say, andpupa of Carabus auronitens of Europe, after Westwood) is a closelyallied form, with very similar habits. 

[Illustration: 221. Carabus and Pupa. ]

[Illustration: 222. Brachinus. ]

[Illustration: 223. Casnonia. ]

[Illustration: 224. Pangus. ]

[Illustration: 225. Agonum. ]

[Illustration: 226. Carabid Larva. ]

A much smaller form is the curious Bombardier beetle, Brachinus (Fig. 222, B. Fumans), with its narrow head and heart-shaped prothorax. It isremarkable for discharging with quite an explosion from the end of itsbody a pungent fluid, probably as a protection against its enemies. Anallied genus is Casnonia (Fig. 223, C. Pensylvanica), which has a longneck and spotted wing covers. Figure 224, Pangus caliginosus, and figure225, Agonum cupripenne, represent two common forms. The former is black, while the latter is a pretty insect, greenish, with purplish-redwing-covers, and black legs. 

Figure 226, enlarged about three times, represents a singular larvafound by Mr. J. H. Emerton under a stone early in spring. Dr. LeConte, to whom we sent a figure, supposes that it may possibly be a larva ofHarpalus, or Pangus caliginosus. It is evidently a young Carabid. Theunder side is represented. 

_The Insects of May. _

During this month there is great activity among the insects. As theflowers bloom and the leaves appear, multitudes wake from their longwinter sleep, and during this month pass through the remainder of theirtransformations, and prepare for the summer campaign. Most insectshibernate in the chrysalis or pupa state, while many winter in thecaterpillar or larva state, such as the larvæ of several Noctuidæ andthe "yellow-bear, " and other caterpillars of Arctia and its allies. Other insects hibernate in the adult or imago form, either as beetles, butterflies or certain species of bees. 

It is well known that the Queen Humble bee winters under the moss, or inher old nest. During the present month her rovings seem to have a moredefinite object, and she seeks some deserted mouse's nest, or hollow ina tree or stump, and there stows away her pellets of pollen, containingtwo or three eggs apiece, which, late in the summer, are to form thenucleus of a well-appointed colony. The Carpenter bees (Ceratina andXylocopa, the latter of which is found in abundance south of NewEngland) are busy in refitting and tunnelling the hollows of the grape;while the Ceratina hollows out the stem of the elder, or blackberry. This little upholsterer bee carpets her honey-tight apartment, storingit with food for her young, and later in the season, in June, several ofthese cartridge-like cells, whose silken walls resemble the finest andmost delicate parchment, may be found in the hollow stems of theseplants. The Mason bee (Osmia) places her nest in a more exposed site, building her earthen cells of pellets of moistened mud, either situatedunder a stone, or in some more sheltered place; for instance, in adeserted oak-gall, ranging half a dozen of them side by side along thevault of this strange domicile. Meanwhile their more lowly relatives, the Andrena and Halictus bees, are engaged in tunnelling the side ofsome sunny bank or path, running long galleries underground, sometimesfor a foot or more, at the farthest end of which are to be found, insummer, little earthen urn-like cells, in which the grubs live upon thepollen stored up for them in little balls of the size of a pea. Later inthe month, the Gall flies (Cynips), those physiological puzzles, stingthe leaves of our oaks of different species, giving rise to the strangeexcrescences and manifold deformities which deface the stems and leavesof our most beautiful forest trees. 

[Illustration: 227. Chrysophanus Thoe. [31]] 31 A: The lower side of thewings is figured on the right side of this and Figs. 228 and 229. 

[Illustration: 228. Argynnis Aphrodite. ]

[Illustration: 229. Melitæa Phaeton. ]

When the Kalmia, Rhodora, and wild cherries are in bloom, many of ourmost beautiful butterflies appear; such are the different species ofChrysophanus (Fig. 227), Lycæna, Thecla and Argynnis (Fig. 228). At thistime we have found the rare larva of Melitæa Phaeton (Fig. 229) clothedin the richest red and velvety black, feeding daintily upon the hazelnut, and tender leaves of the golden rod. In June, it changes to thechrysalis state, and early in July the butterfly rises from the cold, damp bogs, where we have oftenest found it, clad in its rich dress ofvelvety black and red. 

Later still, when the lilac blooms, and farther south the broad-leavedKalmia, the gaily-colored Humming Bird moth (Sesia) visits the flowersin company with the Swallow-tail butterfly (Papilio Turnus). Attwilight, the Hawk moth (Sphinx) darts noiselessly through our gardens, as soon as the honeysuckles, pinks and lilies are in blossom. 

[Illustration: 230. D. 12-punctata. ]

[Illustration: 231. Diabrotica vittata. ]

Among the flies, mosquitoes now appear, though they have not yet, perhaps, strayed far from their native swamps and fens; and theirmammoth allies, the Daddy-long-legs (Tipula), rise from the fields andmould of our gardens in great numbers. 

[Illustration: Fig. 232. Plum Weevil and Young. ]

Of the beetles, those which feed on leaves now become specially active. The Squash beetle (Diabrotica vittata, Fig. 231, and Fig. 230, D. 12-punctata) now attacks the squash plants before they are fairly up;and the Plum weevil (Conotrachelus nenuphar, Fig. 232) will sting thenewly formed fruit, late in the month, or early in June. Many otherweevils now abound, stinging the seeds and fruit, and depositing theireggs just under the skin. So immense are the numbers of insects whichfill the air and enliven the fields and woodlands just as summer comesin, that a bare enumeration of them would overcrowd our pages, and tirethe reader. 

[Illustration: 233. May Fly. ]

A word, however, about our water insects. Late in the month the May fly(Ephemera, Fig. 233) appears, often rising in immense numbers, from thesurface of pools and sluggish brooks. In Europe, whole clouds of thesedelicate forms, with their thin white wings, have been known to falllike snow upon the ground, when the peasants gather them up in heaps toenrich their gardens and farms. 

The Case worms, or Caddis flies (Fig. 234), begin now to leave theirportable houses, formed of pieces of leaves, or sticks and fine gravel, or even of shells, as in an European species, and fly over the water, resting on the overhanging trees. 

A few busy Mosquito Hawks, or Dragon flies (Libellula), herald thecoming of the summer brood of these indefatigable friends of theagriculturist. During their whole life below the waters, theseentomological Herods have slain and sucked the blood of myriads ofinfant mosquitoes and other insects; and now in their new world abovethe waters, with still more intensified powers of doing mischief, happily, however, to flies mostly obnoxious to man, they riot inbloodshed and carnage. 

[Illustration: 234. Different Forms of Case Worms. ]

This is the season to stock the fresh-water aquarium. Go to the nearestbrook, gather a sprig or two of the water cress, which spreads sorapidly, a root of the eel grass, and plant them in a glass dish or deepjar. Pour in your water, let the sand and sediment settle, and then putin a few Tadpoles, a Newt (Salamander), Snails (Limnæa, Planorbis andValvata), Caddis flies and Water beetles, together with the gatheringsfrom a thicket of eel grass, or other submerged plants, being rich inthe young of various flies, Ephemeras, Dragon flies and Water fleas(Entomostraca, Fig. 235), which last are beautiful objects for themicroscope, and in a few days the occupants will feel at home, and theaquarium will be swarming with life, affording amusement and occupationfor many a dull hour, by day or at night, in watching the marvels ofinsect transformations, and plant-growth. 

Among the injurious hymenoptera, which abound late in this month, isthe Rose Saw fly (Selandria rosæ, Fig. 236) and S. Cerasi. The eggs arethen laid, and the last of June, or early in July, the slug-like larvæmature, and the perfect insects fly in July. Various Gall flies now laytheir eggs in the buds, leaves and stems of various kinds of oaks, blackberries, blueberries and other plants. 

[Illustration: 235. Water Flea. ]

[Illustration: 236. Selandria rosæ. ]

Dipterous Gall flies are now laying their eggs in cereals. The Hessianfly (Cecidomyia destructor) has two broods, the fly appearing both inspring and autumn. The fly lays twenty or thirty eggs in a crease in theleaf of the young plant. In about four days, in warm weather, theyhatch, and the pale-red larvæ crawl down the leaf, working their way inbetween it and the main stalk, passing downward till they come to ajoint, just above which they remain, a little below the surface of theground, with the head towards the root of the plant. Here they imbibethe sap by suction alone, and, by the simple pressure of their bodiesbecome imbedded in the side of the stem. Two or three larvæ thusimbedded serve to weaken the plant and cause it to wither and die. Thesecond brood of larvæ remains through the winter in the flax-seed, orpuparium. By turning the stubble with the plough in the autumn and earlyspring, its imago may be destroyed, and thus its ravages may be checked. (Figure 237 represents the female, which is about one-third as large asa mosquito: _a_, the larva; _b_, the pupa; and _c_ represents the jointnear the ground where the maggots live. ) The same may be said of theWheat midge (Cecidomyia tritici), which attacks the wheat in the ear, and which transforms an inch deep beneath the surface. 

[Illustration: 237. Hessian Fly. ]

[Illustration: 238. Turnip Butterfly. ]

Among the butterflies which appear this month are the Turnip butterfly(Pontia oleracea, Fig. 238, ) which lays its eggs the last of the month. The eggs hatch in a week or ten days, and in about two weeks the larvachanges to a chrysalis. Thanaos junevalis and T. Brizo fly late in May. The caterpillars live on the pea and other papilionaceous plants. TheclaAuburniana, T. Niphon, and other species fly in dry, sunny fields, somein April. Argynnis Myrina flies from the last of May through June, and asecond brood appears in August and September. Vanessa J-album and V. Interrogationis appear in May, and again in August and September. Thecaterpillars of the latter species live on the elm, lime and hop-vine. Grapta comma also feeds on the hop. Alypia 8-maculata (Fig. 49) flies atthis time, and in August its larva feeds on the grape. Sphinx gordius, S. 5-maculata (Fig. 239) and other Sphinges and Sesia (the Clear-wingedmoth), appear the last of May. Arctia Arge, A. Virgo, A. Phalerata andother species fly from the last of May through the summer. Hyphantriatextor, the Fall-weaver, is found in May or June. The moth of theSalt-marsh caterpillar appears at this time, and various Cut worms(Agrotis, Fig. 240) abound, hiding in the daytime under stones andsticks, etc. , while various Tineids and Tortrices, or Leaf-rollingcaterpillars, begin to devour tender leaves and buds and openingblossoms of flowers and fruit trees. 

[Illustration: 239. Sphinx 5-maculata, Larva and Pupa. ]

[Illustration: 240. Cut Worm and Moth. ]

The White-pine weevil flies about in warm days. We have found itsburrows winding irregularly over the inner surface of the bark andleading into the sap-wood. Each cell, in which it hibernates, in themiddle of March, contains the yellowish white footless grub. Early inApril it changes to a pupa, and a month after the beetle appears, and ina few days deposits its egg under the bark of old pine trees. It alsooviposits in the terminal shoots of pine saplings, dwarfing andpermanently deforming the tree. Associated with this weevil we havefound the smaller, rounder, more cylindrical, whitish grubs of theHylurgus terebrans, which mines the inner layers of the bark, slightlygrooving the sap-wood. Later in April it pupates, and its habits accordin general with those of Pissodes strobi. Another Pine weevil alsoabounds at this time, as well as Otiorhynchus picipes (Fig. 241), whichinjures beans, etc. 

[Illustration: 241. Garden Weevil. ]

Cylindrical bark-borers, which are little, round, weevil-like beetles, are now flying about fruit trees, to lay their eggs in the bark. Associated with the Pissodes, we may find in April the galleries ofTomicus pini, branching out from a common centre. They are filled upwith fine sawdust, and, according to Dr. Fitch, are notched in the sides"in which the eggs have been placed, where they would remain undisturbedby the beetle as it crawled backwards and forth through the gallery. "These little beetles have not the long snouts of the weevils, hence theycannot bore through the outer bark, but enter into the burrows made thepreceding year, and distribute the eggs along the sides (Fitch). AnotherTomicus, more dangerous than the preceding, feeds exclusively in thesap-wood, running solitary galleries for a distance of two inchestowards the centre of the tree. We figure Tomicus xylographus Say (Fig. 242, enlarged). It is the most formidable enemy to the white pine in theNorth, and the yellow pine in the South that we have. It also flies inMay. Ptinus fur (Fig. 243, much enlarged) is now found in out-houses, and is destructive to cloth, furs, etc. , resembling the Larder-beetle(Dermestes) in its habits. It is fourteen hundredths of an inch inlength. 

[Illustration: 242. Pine Weevil. ]

[Illustration: 243. Ptinus and Larva. ]

_The Insects of June. _

Early in the month the Parsnip butterfly (Papilio Asterias) may be seenflying about, preparatory to laying its eggs for the brood ofcaterpillars which appear in August. At the time of the flowering of theraspberry and blackberry, the young larva of Vanessa Antiopa, one of ourmost abundant butterflies, may be found living socially on the leaves ofthe willow; while the mature larva of another much smaller butterfly, the little Copper skipper (Chrysophanus Americans), so abundant at thistime, may sometimes be found on the clover. It is a short, oval, greenish worm, with very short legs. The dun-colored skippers (Hesperia)abound towards the middle of the month, darting over the flowers of theblueberry and blackberry, in sunny openings in the forests. 

The family of Hawk moths (Sphinges) now appear in greater abundance, hovering at twilight over flower-beds, and, during this time, deposittheir eggs on the leaves of various fruit-trees. The American Tentcaterpillar makes its cocoon, and assumes the pupa state. Thecaterpillar passes several days within the cocoon, in what may becalled the semi-pupa states during which period the chrysalis skin isforming beneath the contracted and loosened larva skin. We onceexperimented on a larva which had just completed its cocoon, to learnhow much silk it could produce. On removing its cocoon it made anotherof the same thickness; but on destroying this second one it spun a thirdbut frail web, scarcely concealing its form. A minute Ichneumonparasite, allied to Platygaster, lays its eggs within those of thismoth, as we once detected one under a bunch of eggs, and afterwardsreared a few from the same lot of eggs. A still more minute egg-parasite(Fig. 244) we have seen ovipositing in the early spring, in the eggs ofthe Canker-worm. 

[Illustration: 244. Canker worm Egg-parasite. ]

Among that beautiful family of moths, the Phalænidæ, comprising theGeometers, Loopers, or Span-worms, are two formidable foes to fruitgrowers. The habits of the Canker worm should be well known. With propercare and well-directed energy, we believe their attacks can be in agreat measure prevented. The English sparrow, doves and otherinsectivorous birds, if there are any others that eat them, should bedomesticated in order to reduce the number of these pests. More carethan has yet been taken should be devoted to destroying the eggs laid inthe autumn, and also the wingless females, as they crawl up the trees inthe spring and autumn to lay their eggs. The evil is usually done beforethe farmer is well aware that the calamity has fallen upon him. As soonas, and even before the trees have fairly leafed out, they should bevisited morning, noon and night, shaken and thoroughly examined andcleared of the caterpillars. By well-concerted action amongagriculturists, who should form a Board of Destruction, numbering everyman, woman and child on the farm, this fearful scourge may be abated bythe simplest means, as the cholera or any epidemic disease can in agreat measure be averted by taking proper sanitary precautions. TheCanker worms hatch out during the early part of May, from eggs laid inthe fall and spring, on the branches of various fruit-trees. Just as thebuds unfold, the young caterpillars make little holes through the tenderleaves, eating the pulpy portions, not touching the veins and midribs. When four weeks old they creep to the ground, or let themselves down byspinning a silken thread, and burrow from two to six inches in the soil, where they change to chrysalids in a day or two, and in this state livetill late in the fall, or until the early spring, when they assume theimago or moth form. The sexes then unite, and the eggs are deposited forthe next generation. 

The Canker worm is widely distributed, though its ravages used to beconfined mostly to the immediate vicinity of Boston. We have seenspecimens of the moth from Illinois. Riley has found it in Missouri. 

[Illustration: 245. Abraxas ribearia. ]

The Abraxas ribearia of Fitch (Fig. 245, moth), the well-known Currantworm, defoliates whole rows of currant bushes. This pretty caterpillarmay be easily known by its body being of a deep golden color, spottedwith black. The bushes should be visited morning, noon and night, andthoroughly shaken (killing the caterpillars) and sprinkled with ashes. 

[Illustration: 246. May Beetle and Young. ]

Among multitudes of beetles (Coleoptera) injurious to the crops, are theMay beetle (Lachnosterna fusca, Fig. 246), whose larva, a large whitegrub, is injurious to the roots of grass and to strawberry vines. TheRose beetle appears about the time of the blossoming of the rose. TheFire-flies now show their light during mild evenings, and on hot sultrydays the shrill rasping song of the male Cicada, for "they all havevoiceless wives, " cuts the air: The Chinch-bug, that fell destroyer ofour wheat crops, appears, according to Harris, in the middle of themonth, and "may be seen in their various stages of growth on all kindsof grain, on corn and herds-grass during the whole summer. " So widelyspread is this insect at present, that we have even detected it inAugust on the summit of Mount Washington. 

[Illustration: 247. Pemphigus. ]

The Diptera, or two-winged flies, contain hosts of noxious insects, suchas the various Cecidomyians, or two-winged Gall flies, which now stingthe culms of the wheat and grasses, and various grains, and leaves oftrees, producing gall-like excrescences of varying form. Legions ofthese delicate minute flies fill the air at twilight, hovering overwheat fields and shrubbery. A strong north west wind, at such times, isof incalculable value to the farmer. Moreover, minute flies, allied tothe house fly, such as Tephritis, Oscinis, etc. , now attack the youngcereals, doing immense injury to grain. 

[Illustration: 248. Apple Bark Louse. ]

Millions of Aphides, or Plant lice, now infest our shade and fruittrees, crowding every green leaf, into which they insert their tinybeaks, sucking in the sap, causing the leaves to curl up and wither. They also attack the stems and even the roots of plants, though theselatter (Pemphigus, Fig. 247) differ generically from the true Plantlice. Fruit trees should be again washed and rubbed to kill off theyoung Bark lice, of which the common apple Bark louse (Aspidiotusconchiformis, Fig. 248), whose oyster-shaped scales may be found inmyriads on neglected trees, is a too familiar example. Another pest ofapple trees is the woolly Blight (Eriosoma lanigera). These insectssecrete from the surface of the body a downy, cottony substance whichconceals the animal, and when they are, as usual, grouped together onthe trees, makes them look like patches of mould. The natural insectenemies of the Plant lice now abound; such are the Lady bugs(Coccinella, Fig. 249); the larva of the Syrphus fly (Fig. 76), whichdevours immense quantities, and the larva of the Golden-eyed, Lace-winged fly (Chrysopa, Fig. 256). 

[Illustration: 249. Coccinella and Young. ]

The last days of June are literally the heyday and jubilee of insectlife. The entomological world holds high carnival, though in thiscountry they are, perhaps, more given to mass-meetings and caucuses. Theearth, the air, and the water teem with insect life. The insects ofmid-summer, now appear. Among the butterflies, the Wood Satyrus(Neonympha Eurythris) skips in its low flight through the pines. Thelarva of Grapta Progne appears on the currants, and feeds beneath theleaves on hot sunny days. The larva of Cynthia cardui may be found onthe hollyhocks; the pupa state lasts twelve days, the butterflyappearing in the middle or last of July. The Hyphantria textor now laysits smooth, spherical eggs in broad patches on the under side of theleaves of the apple, which the caterpillar will ravage in August; andits ally, the Halesidota caryæ, we have found ovipositing the last weekin the month on the leaves of the butternut. The Squash bug, Coreus(Gonocerus) tristis (Fig. 250) is now very abundant, gathering about theroots of the squash vines, often in immense numbers, blackening thestems with their dark, blackish-brown bodies. This insect is easilydistinguished from the yellow striped Squash beetle previouslymentioned, by its much greater size, and its entirely differentstructure and habits. It is a true bug (Hemipter, of which the bed-bugis an example), piercing the leaves and stalks, and drawing out the sapwith its long sucker. 

[Illustration: 250. Squash Bug. ]

In June, also, we have found that beautiful butterfly, Militæa Phaetonrising from the low, cold swamps. Its larva transforms early in June orthe last week in May, into a beautiful chrysalis. The larva hibernatesthrough the winter, and may be found early in spring feeding on theleaves of the aster, the Viburnum dentatum and hazel. It is black anddeep orange-red, with long, thick-set, black spines. 

The Currant borer, Trochilium tipuliforme (Fig. 251), a beautiful, slender, agile, deep blue moth, with transparent wings, flies the lastof the month about currant bushes, and its chrysalids may be found inMay in the stems. Among moths, that of the American Tent caterpillarflies during the last of June and July, and its white cocoons can bedetected under bark, and in sheltered parts of fences and out-houses. 

Among others of the interesting group of Silk worms (Bombycidæ) areLithosa, Crocota and allies, which fly in the daytime, and the differentspecies of Arctia, and the white Arctians, Spilosoma, and Leucarctia, the parent of the Salt-marsh Caterpillar. 

[Illustration: 251. Currant Moth. ]

Many Leaf rollers, Tortrices, are rolling up leaves in various ways fortheir habitations, and to conceal them from too prying birds; and hostsof young Tineans are now mining leaves, and excavating the interior ofseeds and various fruits. Grape-growers should guard against the attacksof a species of Tortrix (Penthina vitivorana) which rolls the leaves ofthe grape, and, according to Mr. M. C. Reed, of Hudson, Ohio, "inmid-summer deposits its eggs in the grape; a single egg in a grape. Itspresence is soon indicated by a reddish color on that side of the yetgreen grape, and on opening it, the winding channel opened by the larvain the pulp is seen, and the minute worm, which is white, with a darkhead, is found at the end of the channel. It continues to feed upon thepulp of the fruit, and when it reaches the seeds, eats out theirinterior; and if the supply from one grape is extinguished before itsgrowth is completed, it fastens this to an adjoining grape with a web, and burrows into it. It finally grows to about one-half of an inch inlength, becomes brown, almost black, the head retaining its cinnamoncolor. When it leaves the grape it is very active, and has the power ofletting itself down by a thread of silk. All my efforts to obtain thecocoons failed until I placed fresh grape leaves in the jar containingthe grapes. The larvæ immediately betook themselves to these, and, cutting a curved line through the leaf thus), sometimes two lines thus(), folded the edge or edges over, and in the fold assumed the chrysalisform. From specimens saved, I shall hope to obtain the perfect insectthis season, and perhaps obtain information which will aid in checkingits increase. Already it is so abundant that it is necessary to examineevery branch of ripe grapes, and clip out the infested berries beforesending them to the table. A rapid increase in its numbers wouldinterfere seriously with the cultivation of the grape in this locality. "

The Rose beetle (Macrodactyla subspinosa) appears in great abundance. The various species of Buprestis are abundant; among them are thePeach-borer (Dicerca divaricata), which may be now found flying aboutpeach and cherry trees; and Chrysobothris fulvogutta, and C. Harrisii, about white pines. A large weevil (Arrhenodes septentrionalis), whichlives under the bark of the white oak, appears in June and July. TheChinch bug begins its terrible ravages in the wheat fields. The variousspecies of Chrysopa or Lace-winged flies, appear during this month. 

_The Insects of July. _

During mid-summer the bees and wasps are very busy building their nestsand rearing their young. The Humble bees, late in June and the first ofthis month, send out their first broods of workers, and about the middleof the month the second lot of eggs are laid, which produce thesmaller-sized females and males, while eggs laid late in the month andearly in August, produce the larger-sized queens, which soon hatch. These hibernate. The habits of their peculiar parasite, Apathus, aninsect which closely resembles the Humble bee, are still unknown. 

[Illustration: 252. White-faced Wasp. ]

The Leaf-cutter bee (Megachile) may be seen flying about with pieces ofrose-leaf, with which she builds, for a period of twenty days, hercells, often thirty in number, using for this purpose, according to Mr. F. W. Putnam's estimate, [32] at least one thousand pieces! The beesreferred to "worked so diligently that they ruined five or sixrose-bushes, not leaving a single unblighted leaf uncut, and were thenforced to take the leaves of a locust tree as a substitute. "

The Paper-making wasps, of which Vespa maculata (Fig. 252), the"White-faced wasp, " is our largest species, are now completing theirnests, and feeding their young with flies. The Solitary wasp (Odynerusalbophaleratus) fills its earthen cells with minute caterpillars, whichit paralyzes with its poisonous sting. A group of mud-cells, each storedwith food for the single larva within, we once found concealed in adeserted nest of the American Tent caterpillar. Numerous species of Woodwasps (Crabronidæ) are engaged in tunnelling the stems of theblackberry, the elder, and syringa, and enlarging and refitting old nailholes, and burrowing in rotten wood, storing their cells with flies, caterpillars, aphides and spiders, according to the habit of eachspecies. Eumenes fraterna, which attaches its single, large, thin-walledcell of mud to the stems of plants, is, according to Dr. T. W. Harris, known to store it with Canker worms. Pelopæus, the Mud-dauber, is nowbuilding its earthen cells, plastering them on old rafters and stonewalls. 

The Saw flies (Tenthredo), etc. , abound in our gardens this month. TheSelandria vitis attacks the vine, while Selandria rosæ, the Rose slug, injures the rose. The disgusting Pear slug-worm (S. Cerasi), often livetwenty to thirty on a leaf, eating the parenchyma, or softer tissues, leaving the blighted leaf. The leaves should be sprinkled with a mixtureof whale-oil soap and water, in the proportion of two pounds of soap tofifteen gallons of water. 

[Illustration: 253. Imported Cabbage Butterfly. ]

Among the butterflies, Melitæa Ismeria, in the south, and M. Harrisii, in the north, are sometimes seen. A second brood of Colias Philodice, the common sulphur-yellow butterfly, appears, and Pieris oleracea visitsturnip-patches. It lays its eggs in June on the leaves, and thefull-grown, dark-green, hairy larva may be found in August. The Pieriarapæ, or imported cabbage butterfly (Fig. 253, male) is now alsoabundant. Its green hairy larva is fearfully prevalent about Boston andNew York. The last of the month a new brood of Grapta comma appears, anda second brood of the larva of Chrysophanus Americanus may be found onthe sorrel. 

The larvæ of Pyrrarctia Isabella hatch out the first week in July, andthe snuff-colored moth enters our windows at night, in company with ahost of night-flying moths. These large moths, many of which areinjurious to crops, are commonly thought to feed on clothes and carpets. The true carpet and clothes moths are minute species, which flutternoiselessly about our apartments. Their narrow, feathery wings are edgedwith long silken fringes, and almost the slightest touch kills them. 

[Illustration: 254. Apple Borer, Larva and Pupa. ]

[Illustration: 255. Lady Bug and Pupa. ]

Among beetles, the various borers, such as the Saperda, or apple treeborer (Fig. 254) are now pairing, and fly in the hot sun about trees. Nearly each tree has its peculiar enemy, which drives its galleries intothe trunk and branches of the tree. Among the Tiger beetles, frequentingsandy places, the large Cicindela generosa and the Cicindela hirticollisare most common. The grotesque larvæ live in deep holes in sand-banks. 

[Illustration: 256. Lace-winged Fly and Eggs. ]

[Illustration: 257. Forceps-tail. ]

The nine-spotted Lady Bug, Coccinella novemnotata (Fig. 255, with pupa)is one of a large group of beetles, most beneficial from their habit offeeding on the plant lice. We figure another enemy of the Aphides, Chrysopa, and its eggs (Fig. 256), mounted each on a long silken stalk, thus placed above the reach of harm. 

Among other beneficial insects belonging to the Neuroptera, is theimmense family of Libellulidæ, or Dragon flies. The Forceps-tail, orPanorpa, P. Rufescens (Fig. 257), is found in bushy fields andshrubbery. They prey on smaller insects, and the males are armed at theextremity of the body with an enormous forceps-like apparatus. 

_The Insects of August. _

During this month great multitudes of bugs (Hemiptera) are found in ourfields and gardens; and to this group of insects the present chapterwill be devoted. They are nearly all injurious to crops, as they live onthe sap of plants, stinging them with their long suckers. Theircontinued attacks cause the leaves to wither and blight. 

The grain Aphis, in certain years, desolates our wheat fields. We haveseen the heads black with these terrible pests. They pierce the grain, extract the sap, causing it to shrink and lose the greater part of itsbulk. It is a most insidious and difficult foe to overcome. 

[Illustration: 258. Leaf-hopper of the Vine. ]

The various leaf-hoppers, Tettigonia (Fig. 258) and Ceresa, abound onthe leaves of plants, sadly blighting them; and the Tettigonias frequentdamp, wet, swampy places. A very abundant species on grass produces whatis called "frog's spittle. " It can easily be traced through all itschanges by frequently examining the mass of froth which surrounds it. Tettigonia Vitis blights the leaf of the grape-vine. It is a tenth of aninch long, and is straw-yellow, striped with red. Tettigonia rosæ, astill smaller species, infests the rose, often to an alarming extent. 

The Notonecta, or water boatman, is much like a Tettigonia, but itswings are transparent on the outer half, and its legs are fringed withlong hairs, being formed for swimming. It rows over the surface inpursuit of insects. Notonecta undulata Say (Fig. 259) is a common formin New England. 

Another insect hunter is the singular Ranatra fusca (Fig. 260). It islight brown in color, with a long respiratory tube which it raises abovethe surface of the water when it wishes to breathe. This speciesconnects the Water-boatman with the Water-skaters, or Gerris, a familiarinsect, of which Gerris paludum (Fig. 261) is commonly seen running overthe surface of streams and pools. 

[Illustration: 259. Notonecta. ]

[Illustration: 260. Ranatra. ]

[Illustration: 261. Water Skater. ]

[Illustration: 262. Pirates. ]

Reduvius and its allies belong to a large family of very useful insects, as they prey largely on caterpillars and noxious insects. Such isPirates picipes (Fig. 262), a common species. It is an ally of Reduviuspersonates, a valued friend to man, as in Europe it destroys thebed-bug. Its specific name is derived from its habit while immature, ofconcealing itself in a case of dust, the better to approach its prey. 

[Illustration: 263. Phymata. ]

Another friend of the agriculturist is the Phymata erosa (Fig. 263). Mr. F. G. Sanborn states that "these insects have been taken in greatnumbers upon the linden trees in the city of Boston, and were seen inthe act of devouring the Aphides, which have infested the shade trees ofthat city for several years past. They are described by a gentleman whowatched their operations with great interest, as 'stealing up to alouse, coolly seizing and tucking it under the arm, then inserting thebeak and sucking it dry. ' They are supposed to feed also on othervegetable-eating insects as well as the plant louse. "

Phytocoris lineolaris swarms in our gardens during this month. It isdescribed and figured in "Harris's Treatise on Insects. " Closely allied, though generally wingless, is that enemy of our peace, the bed-bug. Ithas a small somewhat triangular head, orbicular thorax, and large, round, flattened abdomen. It is generally wingless, having only twosmall wing-pads instead. The eggs are oval, white; the young escape bypushing off a lid at one end of the shell. They are white, transparent, differing from the perfect insect in having a broad, triangular head, and short, thick antennæ. Indeed, this is the general form of lice(Pediculus Vestimenti, and P. Capitis), to which the larva of Cimex hasthe closest affinity. Some Cimices are parasites, infesting pigeons, swallows, etc. , in this way also showing their near relation to lice. Besides the Reduvius, the cockroach is the natural enemy of the bed-bug, and destroys large numbers. Houses have been cleared of bugs after beingthoroughly fumigated with brimstone. 

During this month the ravages of grasshoppers are, in the West, verywide-spread. We have received from Major F. Hawn, of Leavenworth, Kansas, a most interesting account of the Red-legged locust (Caloptenusfemur-rubrum). "They commence depositing their eggs in the latter partof August. They are fusiform, slightly gibbous, and of a buff-color. They are placed about three-fourths of an inch beneath the surface, in acompact mass around a vertical axis, pointing obliquely up and outwards, and are partially cemented together, the whole presenting a cylindricalstructure, not unlike a small cartridge. They commence hatching inMarch, but it requires a range of temperature above 60º F. To bring themto maturity, and under such conditions they become fledged inthirty-three days, and in from three to five days after they enter upontheir migratory flight. 

"Their instincts are very strong. When food becomes scarce at one point, a portion of them migrate to new localities, and this movement takesplace simultaneously over large areas. In their progress they stop at noobstacle they can surmount. In these excursions they often meet withother trains from an opposite direction, when both join in one. 

"The insects are voracious, but discriminating in their choice of food, yet I know of no plant they reject if pressed by hunger; not even thefoliage of shrubs and trees, including pine and cedar. "

[Illustration: 264. Seventeen Year Locust, Eggs and Pupa. ]

During this month the Seventeen-year locust (Cicada septendecim ofLinnæus, Fig. 264) has disappeared, and only a few Harvest flies, as thetwo other species we have are called, raise their shrill cry during thedog-days. But as certain years are marked by the appearance of vastswarms in the Middle States, we cannot do better than to give a briefsummary of its history, which we condense in part from Dr. Harris' work. 

The Seventeen-year locust ranges from South-eastern and WesternMassachusetts to Louisiana. Of its distribution west of the MississippiValley, we have no accurate knowledge. In Southern Massachusetts, theyappear in oak forests about the middle of June. After pairing, thefemale, by means of her powerful ovipositor, bores a hole obliquely tothe pith, and lays therein from ten to twenty slender white eggs, whichare arranged in pairs, somewhat like the grains on an ear of wheat, andimplanted in the limb. She thus oviposits several times in a twig, andpasses from one to another, until she has laid four or five hundredeggs. After this she soon dies. The eggs hatch in about two weeks, though some observers state that they do not hatch for from forty toover fifty days after being laid. The active grubs are provided withthree pairs of legs. After leaving the egg they fall to the ground, burrow into it, and seek the roots of plants whose juices they suck bymeans of their long beaks. They sometimes attack the roots of fruittrees, such as the pear and apple. They live nearly seventeen years inthe larva state, and then in the spring change to the pupa, whichchiefly differs from the larva by having rudimentary wings. The damagedone by the larvæ and pupæ, then, consists in their sucking the sap fromthe roots of forest, and occasionally fruit trees. 

Regarding its appearance, Mr. L. B. Case writes us (June 15) fromRichmond, Indiana: "Just now we are having a tremendous quantity oflocusts in our forests and adjoining fields, and people are greatlyalarmed about them; some say they are Egyptian locusts, etc. Thismorning they made a noise, in the woods about half a mile east of us, very much like the continuous sound of frogs in the early spring, orjust before a storm at evening. It lasted from early in the morninguntil evening. " Mr. V. T. Chambers writes us that it is abounding in thevicinity of Covington, Kentucky, "in common with a large portion of theWestern country. " He points out some variations in color from thosedescribed by Dr. Fitch, from New York, and states that those occurringin Kentucky are smaller than those of which the measurements are givenby Dr. Fitch, and states that "these differences indicate that thegroups, appearing in different parts of the country at intervals ofseventeen years, are of different varieties. " A careful comparison oflarge numbers collected from different broods, in different localities, and different years, would alone give the facts to decide thisinteresting point. Mr. Riley has shown that in the Southern States avariety appears every thirteen years. 

Regarding the question raised by Mr. Chambers, whether the sting of thisinsect is poisonous, and which he is inclined to believe to be in parttrue, we might say that naturalists generally believe it to be harmless. No hemiptera are known to be poisonous, that is, to have a poison-glandconnected with the sting, like that of the bee, and careful dissectionsby the eminent French naturalist, Lacaze-Duthiers, of three Europeanspecies of Cicada, have not revealed any poison apparatus at the base ofthe sting. Another proof that it does not pour poison into the woundmade by the ovipositor is, that the twig thus pierced and wounded doesnot swell, as in the case of plants wounded by Gall flies, which, perhaps, secrete an irritating poison, giving rise to tumors of variousshapes. Many insects sting without poisoning the wound; the bite of themosquito, black fly, flea, the bed bug, and other hemipterous insects, are simply punctured wounds, the saliva introduced being slightlyirritant, and to a perfectly healthy constitution they are notpoisonous, though they may grievously afflict some persons, causing theadjacent parts to swell, and in some weak constitutions induce severesickness. Regarding this point, Mr. Chambers writes: "I have heard--notthrough the papers--within a few days past of a child, within sometwenty miles of this place, dying from the sting of a Cicada, but havenot had an opportunity to inquire into the truth of the story, but thefollowing you may rely on. A negro woman in the employment of A. V. Winston, Esq. , at Burlington, Boone County, Ky. , fifteen miles distantfrom here, went barefooted into his garden a few days since, and whilethere was stung or bitten in the foot by a Cicada. The foot immediatelyswelled to huge proportions, but by various applications theinflammation was allayed, and the woman recovered. Mr. Winston, whorelates this, stands as high for intelligence and veracity as any one inthis vicinity. I thought, on first hearing the story, that probably thesting was by some other insect, but Mr. Winston says that he saw theCicada. But perhaps this proves that the sting is _not_ fatal; thatdepends on the subject. Some persons suffer terribly from the bite of amosquito, while others scarcely feel them. The cuticle of a negro's footis nearly impenetrable, and perhaps the sting would have been moredangerous in a more tender part. " It is not improbable that the stingwas made by a wasp (Stizus) which preys on the Cicada. Dr. Le Baron andMr Riley believe the wound to be made by the beak, which is the moreprobable solution of the problem. 

A word more about the Seventeen-year Cicada. Professor Orton writes usfrom Yellow Springs, Ohio, that this insect has done great damage to theapple, peach, and quince trees, and is shortening the fruit crop verymaterially. By boring into twigs bearing fruit, the branches break andthe fruit goes with them. "Many orchards have lost full two years'growth. Though the plum and cherry trees seemed exempt, they attackedthe grape, blackberry, raspberry, elm (white and slippery), maple, whiteash, willow, catalpa, honey-locust and wild rose. We have traces of theCicada this year from Columbus, Ohio, to St. Louis. Washington andPhiladelphia have also had a visitation. "

[Illustration: 265. Hop Vine Moth and Young. ]

[Illustration: 266. Humble Bee Parasite. ]

We figure the Hop-vine moth and the larva (Fig. 265) which abound onhops the last of summer. Also, the Ilythia colonella (Fig. 266, a, pupa), known in England to be a parasite of the Humble bee. We havefrequently met with it here, though not in Humble bees' nests. The larvæfeed directly upon the young bees, according to Curtis (Farm Insects). The Spindle-worm moth (Gortyna zeæ), whose caterpillar lives in thestalks of Indian corn, and also in dahlias, flies this month. Thewithering of the leaves when the corn is young, shows the presence ofthis pest. The beetles of various cylindrical Bark borers and Blightbeetles (Tomicus and Scolytus) appear again this month. During thismonth the Tree cricket (Oecanthus niveus, Fig. 267) lays its eggs inthe branches of peach trees. It will also eat tobacco leaves. 

[Illustration: 267. Tree Cricket. ]

We figure (268) the moth of Ennomos subsignaria, the larva of which isso injurious to shade trees in New York City. It is a widely diffusedspecies, occurring probably throughout the Northern States. We havetaken the moth in Northern Maine. We have received from Mr. W. V. Andrews the supposed larvæ of this moth. They are "loopers, " that is, they walk with a looping gait, as if measuring off the ground they walkover, whence the name "Geometers, " more usually applied to them. Theyare rather stout, brown, and roughened like a twig of the tree theyinhabit, with an unusually large rust-red head, and red prop-legs, whilethe tip of the body is also red. They are a little over an inch long. 

[Illustration: 268. Ennomos subsignaria. ]

_The Insects of September. _

Few new insects make their first appearance for the season during thismonth. Most of the species which abound in the early part of the monthare the August forms, which live until they are killed by the frostslate in the month. From this cause there is towards the end of the montha very sensible diminution of the number of insects. 

The early frosts warn these delicate creatures of approaching cold. Hence the whole insect population is busied late in the month in lookingout snug winter quarters, or providing for the continuance of thespecies. Warned by the cool and frosty nights, multitudes ofcaterpillars prepare to spin their dense silken cocoons, which guardthem against frost and cold. Such are the "Spinners, " as the Germanscall them, the Silk moths, of which the American Silk worm is a fairexample. The last of September it spins its dense cocoon, in which ithibernates in the chrysalis state. 

The larvæ of those moths, such as the Sphinges, or Hawk moths, whichspin no cocoon, descend deep into the earth, where they transform intochrysalids and lie in deep earthen cocoons. 

The wild bees may now be found frequenting flowers in considerablenumbers. Both sexes of the Humble bee, the Leaf-cutter bee, and othersmaller genera abound during the warm days. 

One's attention during an unusually warm and pleasant day in this monthis attracted by clouds of insects filling the air, especially towardssunset, when the slanting rays of the sun shine through the wingedhosts. On careful investigation these insects will prove to be nearlyall ants, and, perhaps, to belong to a single species. Looking about onthe ground, an unusual activity will be noticed in the ant-hills. Thisis the swarming of the ants. The autumnal brood of females has appeared, and this is their marriage day. 

The history of a _formicarium_, or ant's nest, is as follows: Theworkers, only, hibernate, and are found early in the spring, taking careof the eggs and larvæ produced by the autumnal brood of females. In thecourse of the summer these eggs and larvaæ arrive at maturity, and swarmon a hot sultry day, usually early in September. The females, aftertheir marriage flight, for the small diminutive males seek their companyat this time, descend and enter the ground to lay their eggs for newcolonies, or, as Westwood states, they are often seized by the workersand retained in the old colonies. Having no more inclination to fly, they pluck off their wings and may be seen running about wingless. 

Dr. C. C. Abbot gives us the following account of the swarming of aspecies in New Jersey: "On the afternoon of Oct. 6th, at about 4 P. M. , we were attracted to a part of the large yard surrounding our home, by amultitude of large sized insects that filled the air, and appeared tobe of some unusual form of insect life, judging of them from a distance. On closer inspection these creatures proved to be a brood of red ants(Formica) that had just emerged from their underground home and were nowfor the first time using their delicate wings. The sky, at the time, waswholly overcast; the wind strong, southeast; thermometer 66º Fahr. Taking a favorable position near the mass, as they slowly crawled fromthe ground, up the blades of grass and stems of clover and small weeds, we noted, first, that they seemed dazed, without any method in theirmovements, save an ill-defined impression that they must go somewhere. Again, they were pushed forward, usually by those coming after them, which seemed to add to their confusion. As a brood or colony of insects, their every movement indicated that they were wholly ill at ease. 

"Once at the end of a blade of grass, they seemed even more puzzled asto what to do. If not followed by a fellow ant, as was usually the case, they would invariably fall down again to the earth, and sometimes repeatthis movement until a new comer joined in the ascent, when the_uncertain_ individual would be forced to use his wings. This flightwould be inaugurated by a very rapid buzzing of the wings, as though todry them, or prove their owner's power over them, but which it isdifficult to say. After a short rest, the violent movement of the wingswould recommence, and finally losing fear, as it were, the ant would letgo his hold upon the blade of grass and rise slowly upwards. It could, in fact, scarcely be called flight. The steady vibration of the wingssimply bore them upwards, ten, twenty or thirty feet, until they werecaught by a breeze, or by the steadier wind that was moving at anelevation equal to the height of the surrounding pine and spruce trees. So far as we were able to discover, their wings were of the same use tothem, in transporting them from their former home, that the 'wings' ofmany seeds are, in scattering them; both are wholly at the mercy of thewinds. 

"Mr. Bates, in describing the habits of the Saüba ants (Oecodomacephalotes) says, [33] 'The successful _début_ of the winged males andfemales depends likewise on the workers. It is amusing to see theactivity and excitement which reign in an ant's nest when the exodus ofthe winged individuals is taking place. The workers clear the roads ofexit, and show the most lively interest in their departure, although itis highly improbable that any of them will return to the same colony. The swarming or exodus of the winged males and females of the Saüba anttakes place in January and February, that is, at the commencement of therainy season. They come out in the evening in vast numbers, causingquite a commotion in the streets and lanes. ' We have quoted this passagefrom Mr. Bates' fascinating book, because of the great similarity anddissimilarity in the movements of the two species at this period oftheir existence. Remembering, at the time the above remarks concerningthe South American species, we looked carefully for the workers, in thisinstance, and failed to discover above half a dozen wingless ants aboveground, and these were plodding about, very indifferent, as it appearedto us, to the fate or welfare of their winged brothers. And on diggingdown a few inches, we could find but comparatively few individuals inthe nest, and could detect no movements on their parts that referred tothe exodus of winged individuals, then going on. 

"On the other hand, the time of day agrees with the remarks of Mr. Bates. When we first noticed them, about 4 P. M. , they had probably justcommenced their flight. It continued until nearly 7 P. M. , or aconsiderable time after sundown. The next morning, there was not anindividual, winged or wingless, to be seen above ground; the nest itselfwas comparatively empty; and what few occupants there were seemed to bein a semi-torpid condition. Were they simply resting after the fatigueand excitement of yesterday?

"It was not possible for us to calculate what proportion of these wingedants were carried by the wind too far to return to their old home; butcertainly a large proportion were caught by the surrounding trees; andwe found, on search, some of these crawling down the trunks of thetrees, with their wings in a damaged condition. How near the trees mustbe for them to reach their old home, we should like to learn; and whattells them, 'which road to take?' Dr. Duncan states, [34] 'It wasformerly supposed that the females which alighted at a great distancefrom their old nests returned again, but Huber, having great doubtsupon this subject, found that some of them, after having left the males, fell on to the ground in out-of-the-way places, whence they could notpossibly return to the original nest!' We unfortunately did not note thesex of those individuals that we intercepted in their return (?) trip;but we can not help expressing our belief that, at least in this case, there was scarcely an appreciable amount of 'returning' on the part ofthose whose exodus we have just described; although so many were caughtby the nearer trees and shrubbery. Is it probable that these insectscould find their way to a small underground nest, where there was no'travel' in the vicinity, other than the steady departure ofindividuals, who, like themselves, were terribly bothered with the wingsthey were carrying about with them?" (_American Naturalist. _)

We have noticed that those females that do not return to the old nestfound new ones. In Maine and Massachusetts we have for severalsuccessive years noticed the swarming of certain species of ants duringan unusually warm and sultry day early in September. 

The autumnal brood of Plant lice now occur in great numbers on variousplants. The last brood, however, does not consist exclusively of malesand females, for of some of the wingless individuals previously supposedto be perfect insects of both sexes, Dr. W. I. Burnett found that manywere in reality of the ordinary gemmiparous form, such as thosecomposing the early summer broods. 

The White Pine Plant lice (Lachnus strobi) may be seen laying their longstring of black oval eggs on the needles of the pine. They areaccompanied by hosts of two-winged flies, Ichneumons, and in the nightby many moths which feed on the Aphis-honey they secrete, and whichdrops upon the leaves beneath. 

FOOTNOTES:

[Footnote 30: The right side represents the under side of the wings. ]

[Footnote

[Footnote 32: See "Proceedings of the Essex Institute, " vol. Iv, p. 105. ]

[Footnote 33: Naturalist on the River Amazons, vol. 1, p. 32. ]

[Footnote 34: Transformations of Insects, p. 205. ]

INDEX. 

 Abraxas ribearia, 202. 

 Acarus, 124. 

 Acceleration, theory of evolution by, 167. 

 Achorutes, 145. 

 Adela, 189. 

 Agrion, 109. 

 Agrion, egg-parasite of, 164. 

 Agrotis, 197. 

 Alternation of generations, 168. 

 Alypia, 57, 197. 

 American tent caterpillar, 187. 

 Amnion, 166. 

 Ancestral forms, 151. 

 Andrena, 31, 45, 192. 

 Angle worms, 189. 

 Annelida, 161, 170. 

 Anopheles, 189. 

 Ant, 217. 

 Antenna, origin of, 174. 

 Antherophagus, 49. 

 Ant lion, 115, 182. 

 Ants, 189. 

 Anura, 136, 145, 147. 

 Anurida, 146. 

 Apathus, 47. 

 Aphis, 151, 203. 

 Aphis eater, 75. 

 Aphis of grain, 209. 

 Apple borer, 208. 

 Apple insects, 83. 

 Apple tree borer, 187. 

 April, insects of, 187. 

 Agonum, 191. 

 Aquarium, 195. 

 Arachnida, ancestry of, 189. 

 Archetype, 186. 

 Archetypes in Insects, 150. 

 Arctia, 197. 

 Argas, 123. 

 Argynnis, 193, 197. 

 Army worm, 55. 

 Arrhenodes, 206. 

 Arthropoda, 166. 

 Aspidiotus, 203. 

 Assmus, Edward, on parasites of honey bee, 39. 

 Astoma, 122, 159. 

 August, insects of, 209. 

 Band, primitive, 163, 167. 

 Bark borer, 188, 216. 

 Bark louse, 203. 

 Barnacle, 155. 

 Bed bug, 96, 183. 

 Bees, 17, 168, 206. 

 Bee louse, 41. 

 Beneficial insects, 190. 

 Billings on Eophyton, 158. 

 Bird tick, 84. 

 Black fly, 73. 

 Blight insect, 203. 

 Bombardier beetle, 191. 

 Borer, 187. 

 Bot fly, 77. 

 Botrytis, 47. 

 Brachinus, 191. 

 Brauer, F. , on ancestry of insects, 157. On two larval forms, 175. 

 Braula, 41. 

 Breeze fly, 74. 

 Brephos, 189. 

 Bristle tail, 127. 

 Bruchus, 188. 

 Buprestis, 206. 

 Cabbage butterfly, 55, 207. 

 Caddis fly, 153. 

 Caddis fly larva, 178. 

 Caddis worm, 195. 

 Calendar, Insect, 187. 

 Caloptenus, 211. 

 Calosoma, 190. 

 Campodea, 133, 159, 170, 178. 

 Campodea-stage of insects, 157. 

 Canker worm, 187, 201. 

 Carabidæ, 189, 190. 

 Carabus, 191. 

 Carboniferous insects, 158. Myriopods, 158. Scorpion, 158. 

 Carpenter bee, 192. 

 Carpet fly, 75. 

 Case worms, 195. 

 Casnonia, 191. 

 Caterpillar, origin of, 175, 179. 

 Cecidomyia, 168, 196, 203. 

 Cecidomyia tritici, 197. 

 Centipede, 149. 

 Ceratina, 24, 192. 

 Ceresa, 209. 

 Cestodes, 162. 

 Cheese maggot, 83. 

 Cheese mite, 124. 

 Cheyletus, 119. 

 Chigoe, 86. 

 Chinch bug, 55, 203. 

 Chionea, 85. 

 Chironomus, 168, 189. 

 Chloëon, 170, 180. 

 Chrysobothris, 206. 

 Chrysopa, 171, 182, 208. 

 Chrysophanus, 193, 207. 

 Cicada, 212. 

 Cicindela, 189. 

 Clothes moth, 64, 188. 

 Coccinella, 204. 

 Coddling moth, 188. 

 Coleopterous larvæ, 175. 

 Collembola, 133, 159. 

 Comprehensive type, 154. 

 Compsidea, 90. 

 Conotrachelus, 194. 

 Copepoda, 167. 

 Corydalus, mandibles of, 182. 

 Crab, 155, 156. 

 Crustacea, differences of from insects, 157. 

 Currant borer, 204. 

 Currant worm, 202. 

 Cut worm, 197. 

 Cyclops-like stage, 162. 

 Cynips, 193. 

 Daddy-long-legs, 194. 

 Dawson's discovery of fossil myriopods, 159. 

 Dawson on fossil land plants of Upper Silurian, 158. 

 Degeeria, 143. 

 Demodex, 125, 148, 160. 

 Devil's darning-needle, 106. 

 Devonian formation, insects in, 158. 

 Diabrotica, 194. 

 Dicerca, 206. 

 Dicyrtoma, 142. 

 Diplax, 113, 154. 

 Dipterous gall fly, 196. 

 Dipterous larvæ, 175. 

 Dohrn, Anton, on ancestry of insects, 169. 

 Dragon fly, 106, 171, 195. 

 Dujardinia, 170. 

 Dytiscus, 182. 

 Ear wig, 136. 

 Echinoderes, 169. 

 Egg parasites, 201. 

 Egg parasite of Agrion, 164. 

 Eggs of canker worm, 187. 

 Elm tree insects, 90. 

 Embryology, comparative. 167. 

 Embryology of Podura, 140. 

 Ennomos, 216. 

 Ephemera, 154, 194. 

 Ephydra, 174. 

 Eruciform larva, 175. 

 Euphorberia, 158. 

 Evolution theory, 152. 

 Eyes of insects, 185. 

 Fabre on hyper-metamorphosis, 43. 

 Fall weaver, 197. 

 Fire fly, 202. 

 Flea, 86. 

 Forceps Tail, 171. 

 Forficula, 136. 

 Fossil insects, 158. Myriopods, 158. Scorpion, 158. 

 Foul brood, 40. 

 Gad fly, 74. 

 Galley worm, 149. 

 Gall flies, 193. 

 Gall fly, 72, 203. 

 Gall fly, two-winged, 196. 

 Gamasus, 120. 

 Ganin on embryology of insects, 161. 

 Gegenbaur on tracheæ, 172. 

 Generalized types, 154. 

 Generation, alternate, 168. 

 Gerris, 210. 

 Gerris, egg-parasite of, 166. 

 Gills of insects, 172. 

 Gnat, 71, 189. 

 Gonocerus, 204. 

 Gordius, 46. 

 Gortyna, 215. 

 Grain Aphis, 209. 

 Grape insects, 57. 

 Grape leaf roller, 205. 

 Grape saw fly, 207. 

 Grapta, 189, 204, 207. 

 Grasshopper, 181, 211. 

 Green head, 74. 

 Grimm on parthenogenesis, 168. 

 Hæckel, Ernst, on ancestry of insects, 156. 

 Hairs of insects, 185. 

 Hair worm, 46. 

 Halictus, 31, 192. 

 Handily, A. H. , on Thysanura, 133. 

 Hartt's discovery of fossil insects in New Brunswick, 158. 

 Harvest bugs, 122. 

 Haustellate insects, 183. 

 Hawk moth, 194, 200. 

 Head of insects, mode of formation of, 174. 

 Heart, iv. 

 Hemiptera, 209. 

 Hemipterous larvæ, 175. 

 Hessian fly, 72, 196. 

 Heteropus, 126. 

 Hibernation of insects, 192. 

 Hirudo, 166. 

 Histolysis, 168. 

 Histriobdella, 166. 

 Histriobdella stage of Polynema, 164. 

 Hop vine moth, 215. 

 Horse tick, 84. 

 House fly, 80. 

 Humble bee parasite, 215. 

 Humming bird moth, 194. 

 Hunt on organic life in the Laurentian period, 158. 

 Hylobius pales, 188. 

 Hylurgus terebrans, 188. 

 Hymenopterous larvæ, 175. 

 Hyper-metamorphosis of insects, 166. 

 Hyphantria, 204. 

 Hypodermis, 163. 

 Ichneumon, 161, 201. 

 Illinois, fossil insects of, 159. 

 Ilythia, 215. 

 Injurious insects, 190. 

 Insects, ancestry of, 150. 

 Insects, archetypes of, 150. 

 Insects, beneficial, 190. 

 Insect calendar, 187. 

 Insects, embryology of, 154, 155. 

 Insects, flight of, ix. 

 Insects in the Devonian formation, 158. 

 Insects, metamorphosis of, 166. 

 Insects, origin of, 156. 

 Insects, reason in, 30, 37. 

 Insects, respiration of, 171. 

 Insects, senses of, xiii. 

 Insects, sexes in, 52. 

 Insects, transformations of, xiv, 50. 

 Insects, wingless, 171. 

 Intestinal worms, 161. 

 Isotoma, 140, 143. 

 Itch mite, 125. 

 Ixodes, 117, 123. 

 Japyx, 132. 

 Jaws of insects, origin of, 174. 

 Jelly fishes, 168. 

 Joint worm, 55. 

 Julus, 149, 169. 

 Julus, embryology of, 164. 

 July, insects of, 206. 

 June, insects of, 200. 

 Kowaleusky's researches on embryology of worms, 169. 

 Labium, vi, 165. 

 Lachnosterna fusca, 202. 

 Lachnus, 220. 

 Lady bird, 208. 

 Larva, ernciform, 175. Leptiform, 175. Two kinds of, 175. 

 Larval skin of crustacea, 166. 

 Leaf cutter bee, 26, 206. 

 Leaf roller, 188, 197, 205. 

 Leeches, 166. 

 Legs of insects, 173. 

 Leidy, J. , on internal parasites of insects, 39, 46. 

 Lepidocyrtus, 144. 

 Lepidopterous larvæ, 175. 

 Lepisma, 128. 

 Leptiform larva, 175. 

 Leptus, 120, 155, 159. 

 Lespès, on sense of hearing in insects, xiv. 

 Leucania, 55. 

 Leuckart on embryology of Hirudo, 168. Parthenogenesis, 168. 

 Libellula, 107, 195. 

 Linden tree insects, 90. 

 Linguatula, 160. 

 Lipura, 145. 

 Lithobius, 178. 

 Locust tree insects, 93. 

 Louse, 96, 154. 

 Lubbock's discovery of Pauropus, 149. 

 Lubbock, Sir John, on Thysanura, 133; on the origin of insects, 159, 173. 

 Machilis, 128. 

 Macrodactylus, 206. 

 Macrosila cluentius, 184. 

 Maggot, origin of, 175, 178. 

 Mandible, vi. 

 Mandibles of moths, 183. 

 Mandibulate insects, 183. 

 Mange mite, 125. 

 Marey on the flight of insects, ix. 

 Mason bee, 192. 

 Maxillæ, vi. 

 Maxilla of moths, 184. 

 May beetle, 202. 

 May fly, 194. 

 May, insects of, 192. 

 Mazonia, 158. 

 Meat fly, 82. 

 Meek's discovery of fossil insects in Illinois, 158. 

 Megachile, 26. 

 Melipona, 18. 

 Melitæa, 193, 207. 

 Melitæa Phaeton, 204. 

 Meloë, 21, 42. 

 Metamorphosis of insects, 166, 175; origin of, 179. 

 Miastor, 168. 

 Microgaster, 49. 

 Mites, 116, 149. 

 Mosquito, 68. 

 Mosquito hawk, 195. 

 Mouth-parts of insects, origin of, 173. 

 Mucor, 47. 

 Mud dauber, 207. 

 Müller, Fritz, on ancestry of insects, 156, 169. 

 Müller, J. , on sight in insects, xiii. 

 Murray's discovery of Eophyton in America, 158. 

 Musca, 80, 168. 

 Muscardine, 47. 

 Mycetobia, 73. 

 Myobia, 169. 

 Myriopoda, 149. Ancestry of, 159. 

 Nannophya, 114. 

 Nauplius, 155, 160. 

 Nebalia, 182. 

 Nephelis, 166. 

 Nephopteryx, 49. 

 Neuropterous larvæ, 175. 

 New Brunswick, fossil insects of, 158. 

 Newport, on embryology of Julus, 164. 

 Nicoletia, 131. 

 Nomada, 38. 

 Notonecta, 209. 

 Nova Scotia, fossil insects of, 159. 

 Ocypete, 159. 

 Odynerus, 207. 

 Oecanthus, 216. 

 Oil beetle, 188. 

 Onion fly, 49. 

 Ophioneurus, embryology of, 165. 

 Orchesella, 143. 

 Ornithomyia, 84. 

 Orthopterous larvæ, 175. 

 Osmia, 27. 

 Otiorhynchus, 199. 

 Ovipositor of Cicada, 185. 

 Palpus, vi. Origin of, 174. 

 Pangus, 191. 

 Panorpa, 171, 209. 

 Paper wasp, 207. 

 Papilio Asterias, 200. 

 Papirins, 142. 

 Parasite of insect eggs, 164. 

 Parsnip butterfly, 200. 

 Parthenogenesis, 168. 

 Pasteur on the silk worm disease, 63. 

 Pauropus, 149, 154, 158, 171. 

 Peach borer, 206. 

 Pear slug, 207. 

 Pea weevil, 188. 

 Peck, W. D. , on the habits of Stylops and Xenos, 45, 46. 

 Pelopæus, 207. 

 Pentastoma, 148, 160. 

 Peripatus, 161. 

 Perla, 154. 

 Phora, 40. 

 Phymata, 211. 

 Phytocoris, 211. 

 Pickle worm, 57. 

 Pieris, 55, 197, 207. 

 Pieris brassicæ, egg parasite of, 165. 

 Pine plant louse, 220. 

 Pine weevil, 188, 199. 

 Piophila, 83. 

 Pirates, 210. 

 Pissodes strobi, 188. 

 Plan of structure, 186. 

 Plant louse, 220. 

 Platygaster, embryology of, 161. 

 Plum weevil, 194. 

 Podura, 133, 135, 144, 153, 154, 159, 170. Catch of, 139. Spring of, 137. 

 Podurids, the ancestors of the true insects, 157. 

 Poisonous insects, 214. 

 Polynema, embryology of, 164. 

 Poplar tree insects, 92. 

 Potato insects, 63. 

 Prelarval stage of ichneumons, 168. 

 Primitive band, 163, 166. 

 Primitive insects, 175. 

 Prionus, 93. 

 Procris, 60. 

 Protoleptus, 172, 174. 

 Pseudoneuroptera, 178. 

 Ptinus fur, 200. 

 Putnam, F. W. , on habits of the bees, 19, 26. 

 Pyrrharctia, 207. 

 Ranatra, 210. 

 Rat-tailed fly, 76. 

 Reduvius, 210. 

 Reproduction, virgin, 168. 

 Respiration of insects, 171. 

 Retardation, theory of evolution by, 167. 

 Rose beetle, 206. 

 Rose saw fly, 196. 

 Rose slug, 207. 

 Rotatoria, ancestors of crustacea, 169. 

 Salpa, 168. 

 Saperda, 91, 208. 

 Sarcoptes, 125. 

 Saw fly, 196, 207. 

 Saw of saw fly, 185. 

 Schiödte on the mouth-parts of the louse, 96. 

 Scolopocryptops, 149. 

 Scorpion, fossil, 158. 

 Scudder on fossil insects of New Brunswick and Illinois, 158. 

 Seira, 143. 

 Selandria, 207. 

 Selandria rosæ, 196. 

 September, insects of, 216. 

 Sesia, 194. 

 Seventeen year locust, 212. 

 Sexes, origin of, 152. 

 Sheep tick, 85. 

 Shrimp, 155. 

 Siebold, T. Von, on the ears of grasshoppers, xiv. 

 Siebold on parthenogenesis, 168. 

 Silk worm, 51. 

 Silver witches, 128. 

 Simulium, 73. 

 Sitaris, 44. 

 Smith, F. , on stingless bees, 18. On parasitic bees, 37. 

 Smynthurus, 142. 

 Species, origin of, 152. 

 Sphinx, 194, 197, 200, 207. 

 Spider, 155. 

 Spider fly, 85. 

 Spindle worm, 215. 

 Spinneret of caterpillars, 183; of spiders, 185. 

 Spring, insects of, 187. 

 Spring of Podura, 185. 

 Spring tail, 127. 

 Squash beetle, 194. 

 Squash bug, 204. 

 Sting of bee, 185. 

 Sting, origin of, 165. 

 Stylops, 21, 45, 152, 179, 188. 

 Sucker of insects, 183. 

 Sugar mite, 124. 

 Swarming of ants, 217. 

 Syllis, 170. 

 Syrphus, 75. 

 Tabanus, 74. 

 Tachina, 39, 189. 

 Tailor bee, 26. 

 Tardigrade, 150, 160. 

 Teleas, embryology of, 166. 

 Templetonia, 143. 

 Tent caterpillar, 187. 

 Tenthredo, 207. 

 Tettigonia, 209. 

 Thanaos, 197. 

 Thecla, 197. 

 Thorax of insects, 173. 

 Thysanura, 127, 154. 

 Ticks, 116. 

 Tinea, 64, 188. 

 Tipula, 194. 

 Tomicus, 199. 

 Tomocerus, 137, 143. 

 Tongue of insects, 183. 

 Torell's discovery of Eophyton in Sweden, 158. 

 Tortrices, 205. 

 Tortricidæ, 188. 

 Trachea, iv. 

 Tracheæ, absence of in Polynema, 165. 

 Tracheæ, origin of, 171. 

 Tree cricket, 216. 

 Trichocera hyemalis, 189. 

 Trichodes, 42. 

 Trigona, 18. 

 Trochilium tipuliforme, 205. 

 Trombidium, 120, 159. 

 Trouvelot, L. , on amount eaten by silk worms, vii, 60. 

 Turnip butterfly, 197. 

 Uhler, P. R. , on habits of the dragon fly, 107, 110. 

 Verrill, A. E. , on the parasites of man and the domestic animals, 84. 

 Vine dresser, 59. 

 Virgin reproduction, 168. 

 Wasp, 206. 

 Water bear, 150. 

 Water boatman, 166, 209. 

 Waterhouse, G. R. , on habits of Osmia, 27. 

 Weevil, 179, 188, 194. 

 Weismann on growth of insects, 164. 

 West, Tuffen, on the foot of the fly, viii. 

 Wheat midge, 197. 

 Wine fly, 83. 

 Wingless insects, 171. 

 Wings of insects as respiratory organs, 165. 

 Wings, origin of, 172. 

 Worthen's discovery of fossil insects in Illinois, 158. 

 Worms, the ancestors of insects, 160, 169. 

 Wyman, Jeffries, on the cells of the honey bee, 17. 

 Xenos, 46. 

 Xylobius, 159. 

 Xylocopa, 21. 

 Zaddach on development of worms, insects and crustaceans, 169. 

 Zoëa, 156. 

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