The Animal World, A Book of Natural History Part 49

Another very curious fact about the earwig is that the mother insect heaps her eggs together into a little pile, and sits over them until they are hatched. If you turn over large stones early in the spring you may often find a mother earwig watching over her eggs in this odd manner, and she will allow herself to be torn in pieces rather than desert her charge.

ORTHOPTERA

Next comes this order, the name of which means straight-winged insects, so-called from the way in which the wings are folded. This order contains many very well-known insects.

There is the c.o.c.kroach, for example, which is so common and so mischievous in our houses. It is often called the black beetle, although it is not a beetle at all, and is not black, but dark reddish brown. It is remarkable for several reasons. One is that while the male has large wing-cases and broad, powerful wings, those of the female are very small indeed, so that she cannot possibly fly. And another is that the eggs are laid in a kind of h.o.r.n.y purse, about a quarter of an inch long, with a sort of clasp on one side. These little purses are hidden away in all sorts of dark corners, and if you open one you will find two rows of little eggs inside it, arranged rather like the peas in a pod.

The crickets, too, belong to this order.

Of course you have often heard the big black cricket chirping merrily away in the fields; and in Europe they have a kind called the house-cricket, which comes into the house, and is often spoken of as "the cricket on the hearth" in the kitchen. It is not correct, however, to speak of the "note" or "song" of this insect, for it is not produced in the throat at all, but is caused by rubbing one of the wing-cases upon the other. You will notice, on looking at a cricket, that in each wing-case there is a kind of stout h.o.r.n.y rib, which starts from a thickened spot in the middle. Now in the right wing-case this rib is notched, like a file, and when it is rubbed sharply upon the other the loud chirping noise is produced.

The feelers of the cricket are very long and slender, and at the end of the body of the male are two long hairy bristles, which seem almost like a second pair of feelers, warning the insect of danger approaching from behind. At the end of the body of the female is a long spear-like organ, with a spoon-like tip. This is called the ovipositor, and by means of it the eggs are laid in holes punched in the soil.

Crickets have large wings, and fly rather like the woodp.e.c.k.e.rs, rising and falling in the air at every stroke.

Another kind of cricket lives in holes in the ground, which it digs by means of its front legs. These limbs are formed almost exactly like the fore feet of the mole, and for this reason the insect is known as the mole-cricket. It is generally found in sandy fields, and scoops out a chamber almost as big as a hen's egg at the end of its burrow, in which to lay its eggs and where it lies, showing only its jaws and great front legs until some small creature comes near upon which it may pounce for food.

GRa.s.sHOPPERS

Right here has come a mixing up of names between the English, as spoken and written in Great Britain, and that used in the United States. When an Englishman speaks of a gra.s.shopper he means the related insect which we call a cicada, or katydid, and this _we_ call a locust; but when _he_ says "locust" he refers to what _we_ call "gra.s.shopper."

We suspect he is nearer right than we are, who have unfortunately fallen in with the mistake of some ignorant early settler. At any rate the locusts of which we read in the Bible, and in books of travel in desert regions, are all of the same race as our gra.s.shoppers. None of the cicada tribe could ever do so much damage.

Gra.s.shoppers (to stick to our own name) abound in all warm countries, especially in those which in summer, at least, are hot and dry, such as Egypt, or Syria, or parts of India. They feed exclusively on leaves, blades of gra.s.s, and the like, and are strong fliers; and in countries that are favorable to them, where they are always very plentiful, certain species sometimes become excessively abundant, and then spread over the land, and swarm away to neighboring countries, in such immense numbers that they devour every green leaf and every blade of gra.s.s, or spear of grain, until they leave the ground as bare as if it had been swept by fire.

Nor is this the worst, for wherever they go the females push quant.i.ties of eggs down into the ground. The following summer these eggs hatch, and the devastation of the previous year is repeated, for where before dense clouds of flying gra.s.shoppers descended from the sky, now enormous armies of grubs march over the ground, climb all the plants and bushes, and devour all that has newly sprung up.

Millions may be killed by fire or other means, but it has little effect, and the farmers and grazers of a region so visited are all but ruined--perhaps wholly so.

When, in the last century, men began to settle on the prairies of the far West, they met this plague; and between 1870 and 1880 the gardens and farms and young orchards of Kansas, Nebraska, and other western districts, were ruined again and again. The government sent out several of the wisest entomologists it could employ to study the insects, and they found that these destructive red-legged gra.s.shoppers had their home in the dry foothills of the Rocky Mountains, especially toward the north. They learned a great deal about the habits of the insects, and reported that there seemed no remedy just at hand; but that the more the West was settled and cultivated, the more gra.s.s and other food would be provided for the gra.s.shoppers, so that they would not have to make those wide flights, and the more the plowing of the land and burning of rubbish would destroy their eggs, so that gradually the pest would become less and less, until finally it would cease to be troublesome.

This has turned out to be true, and already the fear of gra.s.shoppers has departed. The same thing is taking place in Egypt and some other improving countries, which no longer suffer from the plague of locusts as they used to do.

The wonderful walking-stick and the leaf-insects also belong to this order. They are so marvelously like the objects after which they are named that as long as they keep still it is almost impossible to see them. They seem to know this perfectly well, and will remain for hours together without moving, waiting for some unwary insect to come within reach, for they are among the insects of prey. They are found in all the warmer parts of the world.

Equally curious, too, is the praying-mantis, which also is very much like a leaf. It has very long front legs, with a row of sharp teeth running along their inner margin, and when it is hungry it holds these limbs over its head, in very much the att.i.tude of prayer. That is why it is called the praying-mantis. Then when an insect comes within reach it strikes at it, and seizes it between the upper and lower parts of these limbs, so that the long spike-like teeth enter its body and hold it in a grip from which there is no escape. These occur in various parts of the world, including the warmer parts of America.

DRAGON-FLIES AND MAY-FLIES

The dragon-flies belong to another division of the _Orthoptera_.

You must know these insects very well by sight, with their long slender bodies and their broad gauzy wings; for they are common in almost all parts of the country, and you can hardly go for a ramble on a sunny day in summer or autumn without seeing them in numbers. There are a good many different kinds. Some have yellow bodies, some blue ones, and some red ones, and the loveliest of all perhaps are the graceful demoiselles, whose wings are rich metallic purple. You may sometimes see these beautiful insects flitting to and fro over streams and ditches.

All the dragon-flies spend the earlier part of their lives in the water.

The grubs are very curious creatures and catch their prey in a curious way. Underneath the head is an organ called the mask. This consists of two h.o.r.n.y joints, which fold upon one another while not in use. At the end of the second joint is a pair of great sickle-shaped jaws, and when the grub sees a victim it swims quietly underneath it, unfolds the mask, reaches up, and seizes it with the jaws. Then it folds the mask again, and by so doing drags the prisoner down against the true jaws, by means of which it is leisurely devoured.

This grub swims, too, in a singular manner. At the end of its body you will notice a short sharp spike. Now this spike really consists of five points, which can be opened out into the form of a star; and in the center of this star is a small round hole, which is really the entrance to a tube running right through the middle of the body. And the grub swims by filling this tube with water, and then squirting it out again with all its force, so that the escaping jet pushes, as it were, against the surrounding water, and drives the insect swiftly forward by the recoil.

Dragon-flies are voracious, and always seem to be hungry. They feed entirely upon other insects, and spend almost all their time in chasing and devouring them.

The May-fly, or June-fly, also belongs to this order. One sometimes sees it in thousands, dancing, as it were, up and down in the air toward evening on warm spring days, in the neighborhood of water. You can always tell this insect by the three long thread-like bristles at the end of its body.

Most people think that this insect only lives for a single day. This, however, is not strictly true, for in damp weather many May-flies live for three or four days. Before they become perfect flies, however, they have lived for nearly two years in the muddy banks of rivers and ponds, in the form of long slender-bodied grubs. These grubs always make their burrows with two entrances, in the form of the letter U turned sideways, so that they can easily leave them without having to turn round.

TERMITES

The most wonderful of all the insects which belong to this order, however, are the termites. Often these creatures are known as white ants, and although they are not really ants, they are certainly very much like them. In Africa they make marvelous nests of clay, which are often twelve or fourteen feet high, and are so very large that a church, a parsonage, and a schoolroom have been built of clay slabs cut from the walls of a single termites' nest! These nests are made up of a wonderful series of chambers and galleries, and in the middle is the royal cell, in which the "king" and "queen" live. For in every termites' nest there is one perfect male and one perfect female, which are treated with very great respect, and have a kind of palace, as it were, all to themselves.

And the rest of the insects in the nest are either imperfect males, which are called soldiers, or imperfect females, which are called workers.

The "king" is quite a handsome and graceful insect, with broad and powerful wings; and the "queen," at first, is very much like him. But they never take more than one flight in the air, and as soon as that is over they actually break off their own wings close to their bodies! Then they burrow into the ground and begin to form a nest. Before long, the workers build the palace for the royal couple; and as soon as they have been shut up inside it the body of the queen swells to a most enormous size, so that she can no longer walk at all. This is because of the vast number of eggs, developing within her body, which she at once begins to lay at the rate of many thousands in a single day. As fast as she lays them they are carried off by the workers, which also take care of the little grubs that hatch out from them, just as bees do.

The duty of the soldiers, as their name implies, is simply to fight, and if a hole is broken in the side of the nest they hurry to the spot at once, and begin to snap with their jaws at the foe. And these jaws are so sharp and so powerful that they can really give a very smart bite.

The workers are a good deal smaller, and they have to build the nest and keep it in repair, to find food for the grubs, and take care of them, and wash them, and feed them, and do everything else that is necessary for the welfare of the colony.

The grubs of these insects are fed upon dead wood, which is generally obtained from the trunks and branches of trees. But termites are sometimes very troublesome in houses, for they will devour the woodwork and the furniture and the books, leaving nothing but a thin sh.e.l.l of wood or paper behind them.

There are a good many different kinds of these wonderful insects, and they are found in warm countries in all parts of the world.

The North American termites do not build great clay hills or houses above ground, but some species make extensive galleries beneath the surface, while others hollow out a dead stump, or the dying branch of a tree, or even an old fence-post or telegraph pole, until it becomes a mere sponge, with a thin outside sh.e.l.l.

NEUROPTERA

The _Neuroptera_, or nerve-winged insects, form an order whose wings are divided up by h.o.r.n.y nerves, or nervures, into such numbers of tiny cells, that they look as if they were made of the most delicate lace.

The caddis-flies belong to this order--brownish insects with long thread-like feelers and broad wings, which are folded tentwise over the body when they are not being used. They are very common near ponds and streams, in which they pa.s.s the earlier part of their lives, living down at the bottom in most curious cases, which cover them entirely up with the exception of their heads.

These cases are made of all sorts of materials. Some caddis-grubs merely fasten two dead leaves together, face to face, and live between them.

Others make a kind of tube out of grains of sand, or tiny stones, or little bits of cut reed, all neatly stuck together with a kind of glue which resists the action of water. But the oddest case of all is made of tiny living water-snails, and you may sometimes see fifteen or twenty little snails all trying to crawl in different directions, while the grub is unconcernedly pulling them along in another!

The grubs never leave these cases, but drag them about with them wherever they go. And when they find that their odd little homes are becoming too small, they just cut off a little piece at the end and add a little piece on in front, rather larger in diameter. And so they always manage to keep their homes of exactly the proper size.

Most likely, too, you have heard of the ant-lion fly, which is a rather large fly with a slender body and four long narrow wings, and is found in many parts of the south of Europe, as well as in America. But the interest lies in the grub, or "ant-lion" proper, which has a most singular way of catching its insect victims. It digs a funnel-shaped pit in the sand, about three inches in diameter and two inches deep, by means of its front legs and its head. Then it almost buries itself at the bottom, and lies in wait to snap up any ants or other small insects which may be unfortunate enough to fall in. And if by any chance they should escape its terrible jaws and try to clamber up the sides, it jerks up a quant.i.ty of sand at them, and brings them rolling down again to the bottom, so that they may be seized a second time.

A relation of the ant-lion is called the lacewing fly, and is a pretty pale-green insect with most delicate gauzy wings, over which, if you look at them in a good light, all the colors of the rainbow seem to be playing; and its eyes glow so brightly with ruby light that one can scarcely help wondering if a little red lamp is burning inside its head.

You may often see it sitting on a fence on a warm summer day, or flitting slowly to and fro in the evening.

This fly lays its eggs in cl.u.s.ters on a twig, or the surface of a leaf, each egg being fastened to the tip of a slender thread-like stalk. The result is that they do not look like eggs at all; they look much more like a little tuft of moss. When they hatch, a number of queer little grubs come out, which at once begin to wander about in search of the little greenfly insects upon which they feed. And when they have sucked their victims dry, they always fasten the empty skins upon their own backs, till at last they are covered over so completely that you cannot see them at all!

CHAPTER x.x.xIII

INSECTS (Continued)