There are different kinds of caddis-flies, however, and the grub of one kind fastens grains of sand together to make a case, while that of another sticks two dead leaves face to face, and lives between them.
It would be an interesting task for a boy or girl to see how many different kinds of caddis-flies, judging by their cases, lived in the stream, and to keep them alive in an aquarium, and watch their behavior and changes.
II
SUMMER
A walk in midsummer is a stroll through what seems a quiet world compared with the noise and brightness of May. Then every leaf was green and crisp, every bird in full song, and the world seemed to have an air of gay youth, like a vigorous boy or girl full of eagerness and activity.
Now as July draws toward its end the eagerness has subsided and the year, like a lad grown a little older and more serious, has settled down to regular work. Had our walk been taken before breakfast, we should have heard no end of birds singing, it is true; but about the time the dew dried from the grass most of them ceased their music. One reason, besides the noonday heat, is that they are too busy to sing, for the husband and father—and he is the singer of the family—must now help his mate feed her young. We fear, however, he is not a very good provider after the fledglings quit the nest, leaving most of their support and schooling to the mother. At this season one may often come upon and watch a little family group of this kind, and perhaps we may do so.
Meanwhile let us sit down for a moment on this grassy bank—not too near that fence-post, for do you not see twined about it that vine with the reddish hairy stem, and the shining leaves in groups of threes? That is the poison-ivy, which may cause an itching rash to break out upon your skin if you touch it. You must learn to recognize and avoid this "ivy"—which is not a true ivy, but a kind of climbing sumach—before you go poking around in the fields, or you will be sorry. Do you notice the delicious beeswax-like odor in the air? That comes from the big yellow branches of blossoms on another and perfectly harmless kind of sumach—that scraggly sort of bush just beyond the fence.
See how the bees are humming about it—some of them honey-bees from a farmer's hive, others big bumblebees and small burrowing kinds. All are in search of the minute drops of sweet liquid which each of the tiny flowers in the blossom-head contains, and which turns into honey after it has been carried a little while in the insect's crop, or lower part of the throat, where it lodges. Then it is suitable to be really swallowed, or to be coughed up and fed to the young bees at home, or stored away in the cells of such bees as store up honey, for many wild bees do not make such stores.
Besides its nectar, however, every flower contains a quantity of small particles, like dust, which are produced in the heads of the little thread-like interior parts of the blossom called the stamens; and in order that the flower shall turn to a seed it is needful that some grains of this dust, or pollen, shall fall upon another hollow part called the pistil, and so pass down into its base. It is much better that the pollen of one flower shall get into the pistil of another than into its own. The wind manages this to some extent—especially for the grasses—by shaking or blowing the loose pollen out of one flower and into another.
But the bees help this process greatly, and so may be said to pay for the sweets they use. Watch this one buzzing in front of that clump of jewelweed. Suddenly the loud humming ceases, and the bee crowds herself into the hanging, bell-like blossom, searching for the nectar. Now she is backing slowly out, and you may see how her furry body is half-powdered with yellow dust. That is pollen; and when she dives into another "jewel" she will brush some of it off against the pistil there, which is right in her way, and is very glad to accept her gift. So the bees and other insects humming about the flowers in this hot sunshine are not only getting their living but helping the plants to keep vigorous and produce lots of healthy seed.
Now let us move on. The sky is filled with swallows. There are the fork-tailed ones that make their nests inside the barn; the square-tailed ones that form their curious bottle-shaped nests of mud on the outside, under the eaves; and the purple martins that live in our bird-house in the garden. They are darting and dashing and skimming about in mid-air as though they did not know what it is to be tired; and if only they were a little closer we should see that every one of them has its mouth wide open. The reason is that these birds have very sticky tongues, and that all the time they are in the air they are chasing flying insects, bothersome gnats and mosquitoes among the rest. As soon as one of these insects is touched by the tongue, it sticks to it. Then, without swallowing it, the bird tucks it away in the upper part of its throat, and goes off to hunt for another. After a time it has quite a ball of little bugs packed away in this curious manner, and can carry no more; so it flies off to its nest, and divides them among its little ones.