How do the insects make their noise—for one can hardly call it singing? That will be a good subject for you to look up in your books. The air is filled with the droning and humming of other insects; how are these sounds produced?
We notice the insect-noises more, perhaps, because other animals are so quiet. It is rare to hear the croak of a frog, or the piping of a tree-toad or the note of a bird. What has become of the birds? When we see a few they are in flocks, and seem very intent on traveling somewhere. The truth is they are gathering in companies and journeying away to the south, where winter, with its cold and snow and hunger, cannot follow them. Next spring they will come back again, to spend the summer with us.
Only those birds remain which can live upon seeds, or pick up rough fare along the sea-shore. A band of small winged friends are flitting about among the weeds ahead of us. Do you not know them? Look closely. Aren't the canary-like form and black wings familiar? You would say they were goldfinches if they were more yellow, wouldn't you? Now you see that that is what they are, but in an olive dress. The fact is that all birds molt their feathers twice a year. In spring the new feathers come out in bright colors, and in autumn there worn gay coats are lost, and feathers of duller hue take their place. Thus the brilliant yellow and black goldfinch of summer becomes a quiet Quaker in winter. Such a change is very advantageous to the birds—how, you may study out for yourselves.
Butterflies are scarce, too, but these have died, not run away, as the birds are doing. One sees a good many sluggish caterpillars, however; and sharp eyes may begin to find cocoons hanging from the bushes, or tucked into crevices of bark, or plastered against rocks and the boards of old fences. If you were to keep account of all the different kinds you could find, you would soon have a long list; and if you were to learn how to keep them properly and care for the butterflies and moths which will come out of them in the spring, you could start an admirable cabinet.
Here is a patch of milkweed. Examine each plant thoroughly because there may be a gift for you hidden among the leaves. You have found "something pretty," you say? What is it like? "Like a green thimble, with rows of gold buttons on it." That is a pretty accurate description; only your thimble is closed at the top, where it hangs by a short thread, and it is heavy and alive, for it is the lovely chrysalis of the milkweed butterfly. Next summer you must learn the appearance of that species, which you can easily do, for it is one of our largest and commonest ones.
Where the milkweeds grow you are pretty sure to see also masses of goldenrod, and towering high above them the great, flowering pillars of joepye-weed. Such clumps are good hunting-places for autumnal insects. There gather the soldier-beetles, brilliant in uniforms of yellow and black. They are sometimes so numerous as to bend down the plants by their weight, and are in constant motion, crawling about the blossoms, or flying from spray to spray. Here, too, come locust-boring beetles, black with a line of yellow V's on the back, whose eggs are laid in the soft inner bark of locust-trees; and fat short-winged blister-beetles, or oil-beetles, which leave such a bad odor on the hands when touched. This is due to an acrid oil which oozes out of the joints of the beetle's legs when it is handled and thinks itself in danger. It is a protection, for it both smells and tastes so nasty that no bird will ever attempt to eat an oil-beetle. And its body is so very big because it lays such an enormous number of eggs. How many eggs do you think an oil-beetle will lay? Why, something like thirty thousand! She lays them in batches in little holes in the ground, and a few days afterward a tiny little grub hatches out of each egg, and begins to hunt about for some flower that bees are likely to visit. When it finds one, it climbs up the stem, hides among the petals, and waits. Then as soon as a bee settles upon the flower it springs upon her and clings to her hairy body. The bee is very busy collecting nectar and pollen, and the grub is very tiny; so she never seems to notice that the long-legged little creature is clinging to her, and carries it back with her to her nest. Then the grub lets go, and proceeds to eat all the "bee-bread" which the bee had stored up so carefully for her own little ones.
How is it that all the trees, bushes, and plants are covered with threads of spider's silk, which often annoys us by getting on our hands or faces? Let us help you to an answer. This is the time of year when spiders are most numerous and most active; and many a spider trails behind it a thread of gossamer wherever it goes, and leaves it there. On many of the plants, bushes, trees, and fences you may see, if you look closely, very small spiders resting. Those little spiders have been taking a journey through the air—a sort of balloon trip. During the summer a number of spiders, all living near one another, had big families—a hundred or more in each. Perhaps you noticed in July and August spiders dragging about large white bundles: they were packets of eggs from which the young hatched. So many coming into the world together made it difficult to find food. So, one by one, the little spiders climbed low bushes or tall plants, and perched themselves on the tips of the topmost leaves. Then each poured out from the end of its body a slender thread of silk, which floated straight up in the warm air rising from the heated ground.
At last each little spider had seven or eight feet of thread rising up into the air above it. Then suddenly it loosed its hold of the leaf, and mounted into the air at the end of its own thread, higher, and higher, and higher, till it had risen several hundreds of feet into the air. Then it met a gentle breeze traveling slowly overhead, and traveled along with it, mile after mile, still resting on its thread. And when it wanted to come down, all that it had to do was to roll up the thread till there was not quite enough left to support it, and so it came floating gently down to the ground below. Then, having no more use for the thread, it broke loose from it and left it lying like a fallen telegraph wire across the tops of the bushes and fences and other things, where our faces brush against it.
What a pretty green fly this is sitting upon the fence, with delicate gauzy wings looking like the most delicate lacework!
Yes, that is a lacewing fly. Just notice what wonderful eyes it has. They look like little globes of crimson fire, and it is quite difficult to believe that a tiny lamp is not alight inside the head. This fly lays its eggs in a most curious way. Settling on a twig, she pours out a drop of a kind of thick gum from the end of her body. Then, jerking her body suddenly upward, she draws out this gum into a slender thread, which hardens as soon as it comes into contact with the air; and just as she lets go she fastens an egg to the tip. She then lays another egg in the same manner, and then another, and then another, and so she goes on till she has laid quite a little cluster of eggs—perhaps ninety or a hundred altogether. You would not think that they were eggs if you were to see them. You would be almost sure to think that the little cluster was a tuft of moss. Indeed, for a great many years even botanists thought that these eggs were a kind of moss, and put pictures of them in books of botany accordingly!