The Animal World, A Book of Natural History Part 51

b.u.t.tERFLIES

It is possible here, of course, to mention only a few of the most striking forms of b.u.t.terflies, out of the many hundreds of species counted as North American. It may be said that these insects are much alike in general features all round the northern half of the globe, the same families being represented, so that, at first glance, European or Asiatic examples of such b.u.t.terflies as the great yellow, black-striped swallowtail seem the same as American examples.

Among the handsomest of all northern b.u.t.terflies is the purple emperor, which you may sometimes see flying round the tops of the tallest trees in large woods in the south of England. Far commoner, however, are the large, small, and green-veined whites, whose caterpillars are so destructive to cabbages; the scarlet admiral, with broad streaks of vermilion across its glossy black wings; the peac.o.c.k, with its four eye-like blue spots on a russet ground; the tortoise-sh.e.l.ls, mottled with yellow and brown and black; and the pretty little blues, which one may see in almost every meadow from the middle of May till the end of September. Then there are the brimstone, with its pale yellow wings, which with the blues dance along the roadways in little whirling companies all summer; the meadow-brown and the large heath, to be seen in thousands in every hayfield; the small heath and the small copper, even more plentiful still; the fritillaries, some of which live in woods, and some on downs, and some in marshy meadows; the pretty orange-tip, with pure white wings tipped with yellow; and the odd little skippers, which flit merrily about gra.s.sy banks in the warm suns.h.i.+ne in May and again in August--besides several others, which are so scarce or so local that hardly anybody ever sees them.

MOTHS

You can easily tell moths from b.u.t.terflies by looking at their antennae, or feelers, which have no k.n.o.bs at the tips, as those of b.u.t.terflies have. Their number also is very great, and we can mention only a few of the most remarkable.

First among these is the splendid death's-head sphinx, or hawk, the largest of all the insects, which sometimes measures five inches from tip to tip of its wings when they are fully spread. It owes its name to the curious patch of light-brown hairs on its thorax, which looks just like a skull. The caterpillar is a huge yellowish creature, often nearly six inches long, with a blue horn at the end of its body, and seven blue stripes, edged with white, on either side. It lives in potato-fields, hiding underground by day and coming out at night to feed upon the leaves. And it is an odd fact that both the caterpillar and the perfect insect have the power of squeaking rather loudly. The moth appears in October.

The humming-bird hawk-moth flies by day, and you may often see it hovering over flowers in the garden, with its long trunk poked down into a blossom in order to suck up the sweet juices. As it does so it makes quite a loud humming noise with its wings, like the little bird from which it takes its name. And sometimes you may see a bee-hawk, which has transparent wings, hovering in front of rhododendron blossoms in just the same way.

The swifts fly between sunset and dark, and the largest of them is very curious indeed. For although it has glossy white wings, so that one can see it quite clearly in the dusk, it will suddenly disappear. The fact is that although its wings are white above they are yellowish brown below; so that when it suddenly settles, and folds them over its back, it at once becomes invisible.

The goat-moths are large, heavily built insects, with brownish-gray wings marked with a number of very short upright dark streaks. The caterpillar is a great reddish-brown creature with a broad chocolate band running down its back. It lives for three years in the trunks of various trees, and then spins a silken coc.o.o.n in which to turn to a chrysalis.

Tiger-moths have brown fore wings streaked with white, scarlet hind wings with bluish-black spots, and bright scarlet body. The caterpillar, which is very common in gardens, is generally called the woolly bear, because of the long brown hairs which cover its body.

Very beautiful indeed are the burnets, which have dark-green front wings, with either five or six large red spots, and crimson hind wings, edged with black. You may often see them resting on flowers and gra.s.s-stems by the roadside in the hot suns.h.i.+ne. And in some parts of the country the cinnabar-moth is almost equally plentiful. You can recognize it at once by the crimson hind wings, and by the streak and the two spots of the same color on the front ones. The caterpillar, which is bright orange in color, with black rings round its body, feeds upon ragwort.

THE CURIOUS VAPORER

The vaporer-moth is very common toward the end of summer, and even in London one may often see it das.h.i.+ng about in the hot suns.h.i.+ne with a strange jerky flight. But one only sees the male, which is a bright brownish-yellow insect measuring about an inch across the wings; for the female is much more like a grub than a perfect insect, and has wings so small that they are hardly visible. Of course she cannot fly; and her body is so big and clumsy that she cannot even walk. So she spends her life clinging to the outside of the coc.o.o.n in which she pa.s.sed the chrysalis state, and covers it all over with her little round white eggs. And when she has laid the last of these she falls to the ground and dies.

Very handsome indeed is the emperor-moth, which has a big eye-like spot in the middle of each wing, something like those of the peac.o.c.k-b.u.t.terfly. But its caterpillar is even more beautiful still, for its body is of the loveliest gra.s.s-green color, sprinkled all over with little pink tubercles, each of which is enclosed in a ring of black, and has a tuft of glossy black hairs sprouting from it. This caterpillar feeds on bramble and heather, and when it reaches its full size it spins a light-brown coc.o.o.n among the leaves of its food-plant, and then turns to a chrysalis, from which the perfect moth hatches out in the following April.

Very often one finds caterpillars which look just like little bits of stick, and which walk in a most curious fas.h.i.+on by hunching up their backs into loops, and then stretching them out again, just as if they were measuring the ground. These caterpillars are called loopers, and they turn into moths with large broad wings and very slender bodies.

There are a great many kinds of these moths. One, called the swallowtail, may often be found hiding among ivy in July. It has large wings of a pale-yellow color, with little tails upon the hinder pair.

Then there are the sulphur, a smaller insect with wings of a brighter yellow; the emeralds, of the most delicate green; the magpie, which has wings of the purest white, marked with streaks of orange and numbers of almost square black spots and blotches; and many others far too numerous to mention. If you ever shake a bush in summer-time you may see quite a dozen of them flying away to seek for some fresh hiding-place.

Then there is a large moth known as the puss, because it is colored rather like a brindled gray cat. The caterpillar is bright green, with a big hump in the middle of its body, and two long thread-like organs at the end of its tail, with which it will sometimes pretend to be able to sting you. But in reality it is perfectly harmless. You may often find it feeding on the leaves of willow-trees in August, and when it is fully fed it spins a hard, oval coc.o.o.n in a crack in the bark. And there are three smaller moths belonging to the same family, which are known as kittens!

Another very large group of moths is that of the _Noctuae_, or night-fliers. But we so seldom see these unless we go out specially to look for them that we shall pa.s.s them by without further mention.

h.o.m.oPTERA

The next order is that of the _h.o.m.optera_, or same-winged insects, which are so called because their upper and lower wings are just alike.

The froghoppers all belong to this order. Do you know them? They are little brown or gray insects, sometimes marked or marbled with white, which carry their wings folded tentwise over their backs, and hop about with really wonderful activity. It has been calculated that if a man of ordinary height could leap as well as a froghopper, in proportion to his greater size, he would be able to cover nearly a quarter of a mile at a single jump!

But if you do not know the froghoppers by sight you must at any rate know something of their grubs; for these are the creatures which cause the cuckoo-spit of which one sees so much during the early summer. Very often the weeds and long gra.s.s in a meadow, or by the roadside, are almost covered with the odd little ma.s.ses of froth, so that one's feet get quite wet as one walks through the herbage. And in the middle of each ma.s.s is a fat little grub, which is sucking up the sap of the plant upon which it is resting, and pouring it out again in frothy bubbles.

The mischievous little aphides, or greenfly insects, also belong to this order. There are many different kinds, some of which do terrible damage to hops and corn and all sorts of cultivated plants. We have already mentioned these when describing the habits of ants, and you will recollect that they have sharp little beaks, which they thrust into young shoots and tender leaves in order to suck up the sap; and that as fast as they do so they pour it out again through two little tubes upon their backs in the form of the thin, sweet, and very sticky liquid which we call honeydew. You will remember, too, how fond ants are of this liquid, and how they "milk" the tiny insects just as if they were little cows.

So, you see, the aphides injure plants in two ways. First, they draw off all their sap, which is really their life-blood; and then they drop this sticky honeydew on to the leaves below, and choke up the little holes by means of which they breathe. And the worst of it is that these insects multiply so rapidly. Where there is one to-day there will be five and twenty to-morrow; and two days later there will be five and twenty times five and twenty; and two days later still there will be five and twenty times five and twenty times five and twenty! Indeed, if it were not for ladybirds and lacewing flies and one or two other insects which feed upon aphides, every green leaf would be destroyed by them in a few months' time.

A very curious fact about these insects is that as long as they can find plenty of food they do not grow any wings. But as soon as the sap becomes scanty or thin, wings make their appearance, so that they can fly away and seek for better food elsewhere.

HETEROPTERA

The order of the _h.o.m.optera_, or same-winged insects, is followed by that of the _Heteroptera_, or different-winged insects, in which that part of the wings nearest to the body is hard and leathery, while the rest is softer and thinner, and is generally almost transparent.

Some of these live upon land, while others spend most of their lives in the water.

The curious bishop's-miters belong to the former group. There are a good many kinds, and some of them are very common. You may see them sitting upon flowers, or resting upon raspberries and blackberries in the suns.h.i.+ne. But although they are sometimes very pretty, we do not advise you to handle them, for they have the power of pouring out a liquid which will make your fingers smell very nasty indeed. And you should be most careful not to eat any fruit on which they have been resting, for they leave a horrible flavor behind them, which is even worse than the smell.

Among those which live in the water there are several most interesting insects. There are the water-striders, for example, which you can see running about on the surface of any pond, and which look like narrow-bodied long-legged spiders. But you will notice that they only have six legs, whereas true spiders always have eight. They skim about on the water by means of the middle and hinder limbs, the front pair being used in catching prey. And when they have caught a victim they suck its juices through their sharp little beaks.

Then there is the water-boatman, which always swims on its back. The reason why it does so is that when its body is in that position it is shaped just like a boat, while its long hind legs serve as a pair of oars. So the little insect really rows itself through the water. On a bright sunny day you may often see it resting on the surface of a pond, with its hind legs thrown forward in readiness for a stroke. And if even your shadow falls upon it, or it feels the vibration of a heavy footstep, it will dive down in a moment to some hiding-place among the weeds.

If you ever catch a water-boatman, be careful how you handle it, or it will give your finger a very painful p.r.i.c.k with its sharp beak.

The water-scorpion, too, is very curious. It is a flat, oval insect, of a dirty-brown color, which looks very much like a piece of dead leaf. It seems to know this quite well, for when it is hungry it always hides among dead leaves down at the bottom of the water, and keeps perfectly still. Then the other insects do not notice it, and as soon as one of them comes within reach it seizes it with its great jaw-like front legs, and plunges its beak into its body.

This insect is called the water-scorpion because it has a long spike at the end of its body, which looks something like a scorpion's sting. It is really a breathing-tube, however, the top of which is poked just above the surface of the water while the insect is lying at the bottom, so as to enable it to breathe quite easily.

APHANIPTERA

The order of the _Aphaniptera_, or unseen-winged insects, is a very small one, consisting only of the fleas. The name has been given to them because their wings are so tiny that, even with the microscope, they can hardly be seen at all.

There are a good many different kinds of fleas, all of which suck the blood of animals through their sharp little beaks. Some of them are able to leap to a really wonderful distance, by means of their powerful hind legs. And they are so wonderfully strong that if a man were equally powerful, in proportion to his greater size, he would easily be able to drag a wagon which a pair of cart-horses could scarcely move!

DIPTERA

The last order of insects is that of the _Diptera_, or two-winged flies, which seem to have two wings only instead of four. But if you look at them closely, you will see a pair of little k.n.o.b-like organs just where the hind wings ought to be. And these little organs, which we call balancers, are really the hind wings in a very much altered form.

Although they are so tiny, and look so useless, these balancers are used in some way during flight; for if they are damaged or lost the insect can no longer balance itself or direct its course in the air.

THE MOSQUITO

The mosquito is a troublesome insect which most of us know only too well; for there are very few of us who have not suffered from the wounds caused by its beak. Its life-history is very interesting. The eggs, which are shaped just like tiny skittles, are laid in the water, and the mother gnat fastens them cleverly together in such a way that they form a little boat, which floats on the surface. After a time a little door opens at the bottom of each egg, and a tiny grub tumbles out into the water. It is a very odd-looking little creature, with a very small head, a very big thorax, and a very long tail; and it mostly floats in the water with its head downward, and the tip of its tail resting just above the surface.

These grubs feed on the little sc.r.a.ps of decaying matter which are always floating in the water of the pond, and they wriggle their way about in the strangest manner, by first doubling up their bodies and then stretching them out, over and over again. After a time they throw off their skins and change to chrysalids, and out of this, a few days later, the perfect gnats make their appearance.

The mosquito is a gnat that has many relatives, some very troublesome, like the black fly. Some gnats have very big bushy feelers, just like big plumes. These are the males, and you need not be afraid of them, for they have no beaks and cannot bite.

CRANE-FLY AND DRONE-FLY

Then there is the crane-fly, whose balancers you can see quite easily.