The How and Why Library/Insects/Section IV
IV. Pygmy Friends That Fly and Hop and Creep
Lions and tigers are such terrible beasts that you are very glad they live in circus menageries, park zoos and far-away jungles. As for dragons, very likely they never lived at all, except in story books, along with mermaids and jobberwocks. But insects could tell you quite a different story. In their world, up in the air, down on the ground, in earth dens and even in the water, are beasts of prey that devour them. The very names of some of them are enough to frighten their victims into spasms. There are dragon-flies, ant-lions, tiger-beetles and spiders. But some of them have quite innocent names, such as frog, toad and lady-bird.
Wouldn't mosquitoes and flies and gnats be indignant, if they knew that we think the dragon fly beautiful? But it is as beautiful as any butterfly, and in its darting, skimming flight it is as swift and graceful as a swallow. It really is the swallow of the insect world. It catches and eats its food on the wing, and it eats nothing but flying creatures smaller than itself. It hunts its small game over ponds and ditches, swamps and marshy shores, just where insects breed by millions. Very likely you call these pretty friends of ours snake feeders and devil's darning needles, but they are too busy feeding themselves to feed snakes, and they can't sting or bite you or sew up your ears, at all. They are as harmless as humming birds.
There are several varieties of dragon flies, darners and damsel flies, but they are all insect feeders. They have very long, slender, stiff bodies of dazzling metal colors, in steel blue, purple, green bronze, copper and silver white- Their four long, narrow, silver-gauze wings are beautifully veined, and are often spotted with white or brown or amber. Their big, jewel eyes stand out from their heads and glitter like automobile lamps. And they have regular snapping-turtle mouths.
On very hot midsummer days there often seems to be nothing on the wing but these glitter-winged dragons of the air, and their swarms of little victims. Some of them skurry to shelter in the water weeds if a cloud blows up, but others love to frolic with the wind, and will even go out over white-capped waves on the sea shore. If food is scarce on the water, some of them will go up Into meadows and orchards and get a lunch of codlin moths and weevils.The green-bodied darner even ventures onto lawns, and eats house flies and mosquitoes there.
When dragon flies alight, which isn't often, for they seem tireless, they keep their wings outspread. The damsel flies fold their slender wings down their darning-needle backs, in the shyest way, as if they didn't want to be noticed. Their name comes from the French —demoiselle—which means young lady. One of the damselflies is so gray and modest that it is called marsh nun.
All these are insect feeders, both in the winged and in the larva stage. They lay their eggs on the waiter, or on the stems of water plants. The larva are not worms or grubs, but imperfect insects something like grasshoppers. They are called nymphs. But you will never see them. They live in the mud and on stems in the water, and they eat tadpole mosquitoes, and other water larva.
There is another insect something like the dragon fly that looks as if it might sting. It has a long, wire-like tail that it can curl over its back and poke into a hole in a tree. This is the ichneumon fly (ik-noo'mon). It often stands on the bark of a tree exactly like a woodpecker, so motionless that you can snapshot it with a kodak. It has very long, jointed legs and feelers, and one kind has a body that flares out behind like a brass horn. Some people think the ichneumon fly bores those holes in trees. But the hole is made by some boring beetle. At the bottom of each hole is a grub that feeds on the wood. The body of that soft, fat grub is just the place the ichneumon fly likes to lay an egg in. Then, when the baby hatches, it eats the grub. The fly will go all over a tree and poke its flexible wire egg-layer into countless holes. This clever creature eats very little, but spends most of its time laying eggs in the larva of moths, butterflies and beetles.
Sometimes you may see an insect that looks like a small dragon fly, but that flaps its four gauze wings, in flying. It lays eggs in tiny sand deserts in the woods, on river banks and sea shores. An innocent looking flier it is, but its larva is a true beast of prey—the cunning,flesh-eating ant-lion. The egg hatches into a clumsy, humped, bug-like creature, with spiny hairs to which wet sand sticks. It has six digging legs, and jaws like a mouse trap. It makes a round pit about as big as would be made by pressing the bottom of a small teacup into the sand. When an ant or other little creeper runs over the edge of the pit, it just naturally slides down hill. Before it can climb out again it is snapped up by the half buried ant-lion.
Another sand-dweller with a lair is the tiger beetle. It is brave in a shiny armor of copper, golden green, sand color or pea green with white spots, and is striped and spotted like a tiger or leopard. Its jaws are long, horny, hooked and toothed, and they shut together like the blades of scissors. The larva of the tiger beetles dig pits in which they lie, mouth and eyes out, snapping up all small insects that come their way.
Did you ever catch a pretty red, black-spotted lady-bird beetle on a rose bush, and say:
Lady-bird, lady-bird, fly away home.
Your house is on fire, your children will burn!
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It fairly leaped in wild alarm, when you let it go. Lady-birds cannot walk well, so they are easily captured, but they can fly. There are black lady-birds with red or yellow spots, too. Do you know why you can find them on rose bushes and fruit trees? They eat those little soft green plant lice, or aphides, that swarm on certain plants. In England gardeners hunt for these neat insects to put into flower gardens, orchards and hop fields. If they couldn't get these little friends in any other way, very likely they'd be willing to pay for them.
French gardeners really do pay four and five cents a piece for ugly, warty little hop toads. Toads eat almost anything—red spiders, flies, wasps, caterpillars and moths. And they just dote on cabbage and green salad worms. Nothing touches the toad. He has no teeth to bite, or claws on his webby feet to fight with, nor a stinger. But he has glands behind his jewel-like eyes with which he can make a dreadful smell. This liquid doesn't cause warts as some people think, but it gives the toad a nice wide field of lonesome-ness. He is a night prowler, coming out at dusk. In the daytime he sits in a shady place taking a mouthful of air at a gulp, now and then.The toad, like his water cousin, the frog, has a long tongue, fastened to the front of his jaw. It unrolls, darts out like lightning, catches an insect on a gummy tip, and snaps back quicker than a wink. A toad can clear a house of cockroaches, and a few in a garden will give you more sound vegetables and fewer worms. Tree toads are useful in forests and orchards, and frogs in ponds and swamps. The garden spider is useful, too. (See Mrs. Garden Spider "At Home.")
There is another very humble, helpless little friend that you should not harm. This is the smooth, pinkish-brown worm that you dig for fish bait. It is a true worm, and not a caterpillar or larva of an insect. Its real name is earth-worm. It eats earth for the water and decaying vegetables, but every bit that it eats passes through its soft body, and is powdered and enriched so it will grow plants better.
After a hard rain you may see sidewalks strewn with their dead bodies. They cannot live without moisture, but too much rain often drowns them out of their burrows. If a living worm is touched it shrinks to half its six or eight inches of length, which shows that the little blind creature can feel, and be afraid. Then you can see that its body is made up of ring muscles. And under a magnifying glass you can find tiny hook-like feet, and a sharp gimlet of a boring nose. That nose bores through and through the soil. One worm, it is said, can turn up a quart of finely powdered earth in a summer. And it must turn up many insect eggs and cocoons, to be eaten or to die. Earth worms is one sign of good soil. When the soil is naturally poor, or is worn out by bad farming, there will be few earthworms in it or none at all. (See Dragon-fly, Ichneumon Fly, Frog, Toad, Lady-bird, Earthworm.)