A Book of Natural History Part 5

Next in the scale come the insects, which comprise four-fifths of all existing animals, and each one of the mighty horde seen in summer has pa.s.sed the winter in some form. One must look for them in strange places and under many disguises; for they cannot migrate, as do the majority of the birds, nor can they live an active life while the source of their food supply, the plants, are inactive.

The majority of those insects which in May or June will be found feeding on the buds or leaves of our trees, or crawling worm-like over the gra.s.s of our lawns, or burrowing beneath the roots of our garden plants, are represented in the winter by the eggs alone. These eggs are deposited in autumn by the mother insect, on or near the object destined to furnish the young, or larvae, their food. Each egg corresponds to a seed of one of our annual plants; being, like it, but a form of life so fas.h.i.+oned and fitted as to withstand for a long period intense cold; the mother insect, like the summer form of the plant, succ.u.mbing to the first severe frost.

Thus myriads of the eggs of gra.s.shoppers are in the early autumn deposited in the ground, in compact ma.s.ses of forty to sixty each.

About mid-April they begin to hatch, and the sprightly little insects, devoid of wings, but otherwise like their parents, begin their life-work of changing gra.s.s into flesh.

[Ill.u.s.tration: HEDGEHOG CATERPILLAR.]

A comparatively small number of insects pa.s.s the winter in the larval or active stage of the young. Of these, perhaps the best known is the brown "woolly worm" or "hedgehog caterpillar," as it is familiarly called. It is thickly covered with stiff black hairs on each end, and with reddish hairs on the middle of the body. These hairs appear to be evenly and closely shorn, so as to give the animal a velvety look; and as they have a certain degree of elasticity, and the caterpillar curls up at the slightest touch, it generally manages to slip away when taken into the hand. Beneath loose bark, boards, rails, and stones, this caterpillar may be found in mid-winter, coiled up and apparently lifeless. On the first bright, sunny days of spring it may be seen crawling rapidly over the ground, seeking the earnest vegetation which will furnish it a literal "breakfast." In April or May the chrysalis, surrounded by a loose coc.o.o.n formed of the hairs of the body interwoven with coa.r.s.e silk, may be found in situations similar to those in which the larva pa.s.sed the winter. From this, the perfect insect, the Isabella tiger moth, _Pyrrharctia isabella_ Smith, emerges about the last of June. It is a medium sized moth, dull orange in color, with three rows of small black spots on the body, and some scattered spots of the same color on the wings.

By breaking open rotten logs one can find in mid-winter the grubs or larvae of many of the wood-boring beetles, and, beneath logs and stones near the margins of ponds and brooks, hordes of the maggots or larvae of certain kinds of flies may often be found huddled together in great ma.s.ses. The larvae of a few b.u.t.terflies also live over winter beneath chips or bunches of leaves near the roots of their food plant, or in webs of their own construction, which are woven on the stems close to the buds, whose expanding leaves will furnish them their first meal in spring.

Many insects pa.s.s the winter in the quiescent or pupal stage; a state exceedingly well fitted for hibernating, requiring as it does, no food, and giving plenty of time for the marvellous changes which are then undergone. Some of these pupae are enclosed in dense silken coc.o.o.ns, which are bound to the twigs of the plants upon which the larvae feed, and thus they swing securely in their silken hammocks through all the storms of winter. Perhaps the most common of these is that of the brown Cecropian moth, _Attacus cecropia_ L., the large oval coc.o.o.n of which is a conspicuous object in the winter on the twigs of our common shade and fruit trees. Many other pupae may be found beneath logs or on the under side of bark, and usually have the chrysalis surrounded by a thin covering of hairs, which are rather loosely arranged. A number pa.s.s the cold season in the earth with no protective covering whatever. Among these is a large brown chrysalis with a long tongue case bent over so as to resemble the handle of a jug. Every farm boy has ploughed or spaded it up in the spring, and is it but the pupa of a large sphinx moth, _Protoparce celeus_ Hub., the larva of which is the great green worm, with a "horn on its tail," so common on tomato plants in the late summer.

[Ill.u.s.tration: CHRYSALIS OF TOMATO WORM.]

Each of the winter forms of insects above mentioned can withstand long and severe cold weather--in fact, may be frozen solid for weeks and retain life and vigor, both of which are shown when warm weather and food appear again. Indeed, it is not an unusually cold winter, but one of successive thawings and freezings, which is most destructive to insect life. A mild winter encourages the growth of mould which attacks the hibernating larvae and pupae as soon as, from excess of rain or humidity, they become sickly; and it also permits the continued activity of insectivorous mammals and birds. Thus, moles, shrews, and field mice, instead of burying themselves deeply in the ground, run about freely during an open winter and destroy enormous numbers of pupae; while such birds as the woodp.e.c.k.e.rs, t.i.tmice, and chickadees are constantly on the alert, and searching in every crevice and cranny of fence and bark of tree for the hibernating larvae.

Of the creeping, wingless creatures, which can ever be found beneath rocks, rails, chunks, and especially beneath those old decaying logs which are half buried in the rich vegetable mould, the myriapods, or "thousand-legs," deserve more than a pa.s.sing notice. They are typical examples of that great branch of the animal kingdom known as _arthropods_, which comprises all insects and crustaceans. Each arthropod has the body composed of rings placed end to end and bearing jointed appendages, and in the myriapods each ring and its appendages can be plainly seen; whereas in the higher forms of the branch many of the rings are so combined as to be very difficult to distinguish.

Full forty kinds of myriapods occur in any area comprising one hundred square miles in the eastern United States. About twenty-five of them go by the general name of "thousand-legs" or millipedes, as each has from forty to fifty-five cylindrical rings in the body, and two pairs of legs to each ring. The other fifteen belong to the "centipede"

group, the body consisting of about sixteen flattened segments, or rings, each bearing a single pair of legs. When disturbed, the "thousand-legs" generally coils up and remains motionless, shamming death, or "playing possum," as it is popularly put, as a means of defence; while the centipede scampers hurriedly away and endeavors to hide beneath leaf, chip, or other object.

[Ill.u.s.tration: CENTIPEDE.]

All those found in the Northern States are perfectly harmless, the true centipede, whose bite is reputed much more venomous than it really is, being found only in the South. True, some of the centipede group can pinch rather sharply with their beetle-like jaws; and one, our largest and most common species, a brownish red fellow about three inches long and without eyes, can even draw blood if its jaws happen to strike a tender place. When handled it always tries to bite, perhaps out of revenge for the abominably long Latin name given it by its describer. In fact the name is longer than the animal itself--_Sco-lo-po-cryp-tops s.e.x-spi-no-sus_ (Say)--being its cognomen in full. With such a handle attached to it, who can blame it for attempting to bite? Yet, to the scientist up on his Latin, each part of the above name bears a definite and tangible meaning. All the myriapods found in the woods and fields feed upon decaying vegetation, such as leaves, stems of weeds, and rotten wood, and in winter three or four species can usually be found within or beneath every decaying log or stump. One species with very long legs, _Scutigera forceps_ (Raf.), is often found in damp houses or in cellars. It is sometimes called the "wall-sweeper," on account of its rapid ungainly gait, and is even reputed to prey upon c.o.c.kroaches and other household pests.

Spiders, which do not undergo such changes as do most of the common, six-footed insects, winter either as eggs or in the mature form. The members of the "sedentary" or web-spinning group, as a rule, form nests in late autumn, in each of which are deposited from fifty to eighty eggs, which survive the winter and hatch in the spring, as soon as the food supply of gnats, flies, and mosquitoes appear. The different forms of spiders' nests are very interesting objects of study. Some are those close-spun, flat, b.u.t.ton-shaped objects, about half an inch in diameter, which are so common in winter on the under side of bark, chunks and flat rocks. Others are balloon-shaped and attached to weeds. Within the latter the young spiders often hatch in early winter, make their first meal off their empty egg cases, and then begin a struggle for existence, the stronger preying upon the weaker until the south winds blow again, when they emerge and scatter far and wide in search of more nutritious sustenance.

The "wandering" spiders never spin webs, but run actively about and pounce upon their prey with a tiger-like spring. Six or eight of the larger species of this group winter in the mature form beneath logs and chunks, being often frozen solid during cold weather, but thawing out as healthy as ever when the temperature rises. Retiring beneath the loose-fitting bark of hickory or maple trees, a number of the smaller tube-weaving spiders construct about themselves a protecting web of many layers of the finest silk. Within this snug retreat they lie from November until April--a handsome, small, black fellow, with green jaws and two orange spots on his abdomen, being the most common species found motionless within this seeming shroud of silk on a day in mid-winter.

In any Northern State as many as four hundred different kinds of the six-footed or true insects, in the winged or adult stage, may be taken in winter by any one who is so disposed, and knows where to search for them. Among the _Orthoptera_, the "grouse gra.s.shoppers" live during the cold season beneath the loose bark of logs, or beneath the bottom rails of the old Virginia worm fences. From these retreats every warm, sunny day tempts them forth in numbers. On such occasions the earth seems to swarm with them, as they leap before the intruder, their hard bodies striking the dead leaves with a sound similar to that produced by falling hail. The common field cricket belongs also to the _Orthoptera_, and the young of various sizes winter under rails and logs, bidding defiance to Jack Frost from within a little burrow or pit beneath the protecting shelter.

[Ill.u.s.tration: CHINCH BUG.]

The true bugs, or _Hemiptera_, hibernate in similar places; squash bugs, chinch bugs, "stink" bugs, and others being easily found in numbers beneath loose bark or hidden between the root leaves of mullein and other plants.

Nearly three hundred species of _Coleoptera_, or beetles, occupy similar positions. Almost any rotten log or stump when broken open discloses a half dozen or more "horn" or "bess beetles," _Pa.s.salus cornutus_ L., great, s.h.i.+ning, clumsy, black fellows with a curved horn on the head. They are often utilized as horses by country children, the horn furnis.h.i.+ng an inviting projection to which may be fastened, by a thread or cord, chips and pieces of bark to be dragged about by the strong and never lagging beast of burden. When tired of "playing horse" they can make of the insect an instrument of music; for, when held by the body, it emits a creaking, hissing noise, produced by rubbing the abdomen up and down against the inside of the hard, h.o.r.n.y wing covers. This beetle pa.s.ses its entire life in cavities in the rotten wood on which it feeds, and when it wishes a larger or more commodious home it has only to eat the more.

[Ill.u.s.tration: THIRTEEN-SPOTTED LADY BEETLE.]

The handsome and beneficial lady beetles winter beneath fallen leaves or between and beneath the root leaves of the mullein and the thistle.

Our most common species, the thirteen-spotted lady beetle, _Megilla maculata_ De G., is gregarious, collecting together by thousands on the approach of cold weather, and lying huddled up like sheep until a breath of spring gives them the signal to disperse. Snout beetles galore can be found beneath piles of weeds near streams and the borders of ponds or beneath chunks and logs in sandy places. All are injurious, and the farmer by burning their hibernating places in winter can cause their destruction in numbers. Rove beetles, ground beetles, and many others live deep down in the vegetable mould beneath old logs, where they are, no doubt, as secure from the ice king as if they followed the swallow to the tropics.

Of the _Diptera_, or flies, but few forms winter in the perfect state, yet the myriads of house flies and their kin, which next summer will distract the busy house-wife, are represented in winter by a few isolated individuals which creep forth occasionally from crevice or cranny and greet us with a friendly buzz.

In mid-winter one may also see in the air swarms of small, gnat-like insects. They belong to this order and live beneath the bark of freshly fallen beech and other logs. On warm, sunny days they go forth in numbers for a sort of rhythmical courts.h.i.+p; their movements while in the air being peculiar in that they usually rise and fall in the same vertical line--performing a curious aerial dance which is long continued.

Among the dozen or more b.u.t.terflies and moths which winter in the perfect state, the most common and the most handsome is the "Camberwell beauty" or "mourning cloak," _Vanessa antiopa_ L., a large b.u.t.terfly whose wings are a rich purplish brown above, duller beneath, and broadly margined with a yellowish band. It is often found in winter beneath chunks which are raised a short distance above the ground, or in the crevices of old snags and fence rails. It is then apparently lifeless, with the antennae resting close along the back, above which the wings are folded. But one or two warm days are necessary to restore it to activity, and I have seen it on the wing as early as the 2d of March, hovering over the open flowers of the little snow trillium.

All the species of ants survive the winter as mature forms, either in their nests in the ground or huddled groups in half rotten logs and stumps; while here and there beneath logs a solitary queen b.u.mble-bee, bald hornet, or yellow jacket is found--the sole representatives of their races.

Thus insects survive the winter in many ways and in many places, some as eggs, others as larvae, still others as pupae, and a large number as adults--all being able to withstand severe cold and yet retain vitality sufficient to recover, live, grow, and replenish the earth with their progeny when the halcyon days of spring appear once more.

In the scale of animal life the vertebrates or back-boned animals succeed the insects. Beginning with the fishes, we find that in late autumn they mostly seek some deep pool in pond or stream at the bottom of which the water does not freeze. Here the herbivorous forms eke out a precarious existence by feeding upon the innumerable diatoms and other small plants which are always to be found in water, while the carnivorous prey upon the herbivorous, and so maintain the struggle for existence. The moving to these deeper channels and pools in autumn and the scattering in the spring of the a.s.sembly which has gathered there const.i.tute the so-called "migration of fishes," which is far from being so extensive and methodical as that practiced by the migratory birds.

Many of the smaller species of fishes, upon leaving these winter resorts, ascend small, clear brooks in large numbers for the purpose of depositing their eggs; as, when hatched in such a place, the young will be comparatively free from the attacks of the larger carnivorous forms. Among the lowest vertebrate often found in numbers in early spring in these meadow rills and brooks is the lamprey, _Ammoctes branchialis_ (L.), or "lamper eel," as it is sometimes called. It has a slender eel-like body, of a uniform leaden or blackish color, and with seven purse-shaped gill openings on each side. The mouth is fitted for sucking rather than biting, and with it they attach themselves to the bodies of fishes and feed on their flesh, which they sc.r.a.pe off with their rasp-like teeth. Later in the season they disappear from these smaller streams, probably returning in midsummer to deeper water. Th.o.r.eau, who studied their habits closely, says of them: "They are rarely seen on their way down stream, and it is thought by fishermen that they never return, but waste away and die, clinging to rocks and stumps of trees for an indefinite period; a tragic feature to the scenery of the river bottoms worthy to be remembered with Shakespeare's description of the sea floor."

[Ill.u.s.tration: A LAMPREY.]

A few of the fishes, as the mud minnow and smaller catfishes, together with most frogs, turtles, and salamanders, on the approach of winter, burrow into the mud at the bottom of the streams and ponds, or beneath logs near their margins. There they live without moving about and with all the vital processes in a partially dormant condition, thus needing little if any food.

The box tortoise or "dry land terrapin," the common toad, and some salamanders burrow into the dry earth, usually going deep enough to escape frost; while snakes seek some crevice in the rocks or hole in the ground where they coil themselves together, oftentimes in vast numbers, and prepare for their winter's sleep. In an open winter this hibernation is often interrupted, the animal emerging from its retreat and seeking its usual summer haunts as though spring had come again.

Thus I have, on one occasion, seen a soft-sh.e.l.led turtle moving gracefully over the bottom of a stream on a day in late December, and have in mid-January captured snakes and salamanders from beneath a pile of drift-wood, where they had taken temporary refuge.

[Ill.u.s.tration: TURTLE.]

With frogs, especially, this hibernation is not a perfect one, and there is a doubt if in a mild winter some species hibernate at all.

For example, the little cricket frog or "peeper" has been seen many times in mid-winter alongside the banks of flowing streams, and during the open winter of 188889 numerous specimens of leopard and green frogs were seen on different occasions in December and January, while on February 18th they, together with the "peepers," were in full chorus.

Of our mammals, a few of the rodents or gnawers, as the ground-hogs, gophers and chipmunks, hibernate in burrows deep enough to escape the cold, and either feed on a stored supply of food, or, like the snakes and crayfish, do not feed at all.

[Ill.u.s.tration: CHIPMUNK.]

Others, as the rabbits, field-mice, and squirrels, are more or less active and forage freely on whatever they can find, eating many things which in summer they would spurn with scorn. To this cla.s.s belongs that intelligent but injurious animal the musquash or muskrat. Those which inhabit the rivers and larger streams live in burrows dug deep beneath the banks, but those inhabiting sluggish streams and ponds usually construct a conical winter house about three feet in diameter and from two to three feet in height. These houses are made of coa.r.s.e gra.s.ses, rushes, branches of shrubs, and small pieces of driftwood, closely cemented together with stiff, clayey mud. The top of the house usually projects two feet or more above the water, and when sun-dried is so strong as to easily sustain the weight of a man. The walls are generally about six inches in thickness and are very difficult to pull to pieces. Within is a single circular chamber with a shelf or floor of mud, sticks, leaves and gra.s.s, ingeniously supported on coa.r.s.e sticks stuck endwise into the mud after the manner of piles. In the centre of this floor is an opening, from which six or eight diverging paths lead to the open water without, so that the little artisan has many avenues of escape in case of danger. These houses are often repaired and used for several winters in succession, but are vacated on the approach of spring. During the summer the muskrat is, in the main, a herbivorous animal, but in winter necessity develops its carnivorous propensities and it feeds then mainly upon the mussels and crayfish which it can dig from the bottom of the pond or stream in which its house is built.

The bats pa.s.s the winter in caves, the attics of houses, and barns, or in hollow trees, hanging downward by their hind claws. Motionless for months they thus remain, and those in the more exposed situations are, doubtless, frozen solid. Yet, in time, their blood flows freely once again and they become as expert on the wing as though the year were one continual jubilee of insect chasing, and frost and snow were to them unknown.

All the carnivora, or flesh-eaters, as the mink, skunk, opossum, fox, and wolf, are in winter active and voracious, needing much food to supply the necessary animal heat of the body. Hence they are then much more bold than in summer, and the hen yard or sheep pen of the farmer is too frequently called upon to supply this extra demand.

[Ill.u.s.tration: A WOLF.]

But of all our animals it seems to me the birds have solved the winter problem best. Possessing an enduring power of flight and a knowledge of a southern sunny sky, beneath which food is plentiful, they alone of all the living forms about us have little fear of the coming of the frost. True, fifty or more species remain in each of the Northern States during the cold season, but they are hardy birds which feed mainly upon seeds, as the snow-bird and song sparrow; on flesh, as the hawks and crows; or on burrowing insects, as the nut-hatches and woodp.e.c.k.e.rs.

Such are some of the solutions to the problem of life in winter which the plants and animals about us have worked out; such some of the forms which they undergo; the places which they inhabit.

To the thinking mind a knowledge of these solutions but begets other and greater problems, such as how can a living thing be frozen solid for weeks and yet retain vitality enough to fully recover? How can a warm-blooded animal sleep for months without partaking of food or drink? And greater than either, what is that which we call life?

I hold in my hand two objects, similar in size, color, organs, everything--twins from the same mother in all outward respects. One pulsates and throbs with that which we call "life." It possesses heat, bodily motion, animal power. The other is cold, motionless, pulseless, throbless--a thing of clay. What is that "life" which the one possesses and the other lacks? Ah, there's the rub! With the wisest of men we can only answer, "_Quien sabe?_" (Who knows?)

[Ill.u.s.tration: WINTER HOUSE OF MUSKRAT.]

BIRDS' NESTS

(FROM WAKE ROBIN.)[3]