LESSON XXXI.
WHIRLIGIG BEETLES.
There is a Mrs. Water-Beetle who has on the under side of her body two little knobs for spinning silk. These are much like the silk-spinners of Mrs. Spider.
As soon as this Mrs. Beetle has laid some eggs, she goes to work, like a good mother, to keep her babies safe and warm. She spins a little silk ball, or bag, for the eggs. This ball is water-tight. It is woven so close that it does not leak. It is so light that it will float.
There are other beetles, and fish, and frogs in thewater, that are seeking food, and they might eat these eggs, but will not touch them when in this tough silk ball. The balls are of a fine bright color, like gold thread.
Another of the water-beetles makes a little silk bag, packs it full of eggs, and glues it to the under side of a leaf of some water-plant.
You know that a fly has a little pair of wings, called alulets, below its true wings. One of the beetles has such clubs or alulets. So you see in one part they are somewhat like a spider, in another part somewhat like a fly. And some things about them are like what a crab has.
Among all animals you will find points of likeness between one creature and another.
Did you ever see a whirligig beetle? He takes his name from the top, or whirligig, because he spins round, and round, and round. Go to the pond, and you will see some of these merry fellows. They act as if they felt so happy that they could not keep still.
These whirligigs are of a fine bronze color. They use their hind legs for oars, and their fore legs for rudders. They have their eyes divided, so that each one seems to have a pair of eyes on each side of its head; one half the eye looks up, and one looks down.
These are small beetles, and they whirl, whirl, whirl. Then they stand still for a second. If you make a dart at them, and try to catch them, you will find that it is not easy to do so.
These whirlers lay their eggs on leaves above water. The larvæ spin silk pupa-cases which hang on leaves, or on stems, above the top of the water.
These and other water-beetles live in ponds or very quiet streams, not in swift water.
I hope the peep you have had at beetle-life will make you wish to study it more. Study not so much in books, as out-of-doors for yourself.
Of what use are beetles? Wise people have not yet found out very much about the use of beetles. Some of them, as you have read, devour or bury spoiled things, that it would be bad to have lying about on the ground. They help to keep the world clean.
Some of them eat insects that harm plants. Some of them make good food for fish, birds, and other creatures. But very many of the beetles do much harm to plants, clothes, and other valuable things. On the whole, I fear that beetles are pretty rather than useful!