As the water-beetles will swim much and walk very little, their first and second pairs of legs are small and feeble, but the hind legs are wide and strong, and reach far back. They are used for swimming.
Mr. Swimming Crab has broad hind legs, used for oars or paddles. Mr. Water-Beetle’s legs are made in much the same way, and have hairs or bristles upon them.
Though the water-beetles are to walk but little, they are to fly much, and so their wings are fine and large.
In fact, the water-beetle likes to fly. Very often he flies at night, and he seems to delight in a clear moonlight. Then the water of his pond spreads out like a sheet of silver, and the crickets chirp in the grass. The air is moist and cool; it is sweet with the scent of flowers.
On such nights the water-beetles rise quite high into the air, and fly here and there, as if full of joy. Then they turn, close their wings, and drop into the water with a plash, like a stone.
When a number of these beetles drop with this quick plash, what do you think happens? Why, the green frogs who sit on logs or rocks, with their big eyes above the water, dive in a great fright. I wonder if the beetles think it is fun to scare the frogs? The frogs give a loud croak as they dive.
The larvæ of water-beetles live in the water, as their parents do. They are very greedy, and hunt their food as if they were angry. They have large jaws, shaped like a sickle. Their bodies are long and narrow, and they have on each side of the head six tiny eyes.
With so many eyes, they can see all about them, so they keep out of danger. They also see bugs which they wish to catch. Their straight, narrow bodies dart through the water with such quick motion as Mr. Crab has when he runs on the sand. They pounce on their prey, and their curved jaws hold it fast.
Some of these great water-beetles have a sharp point, like a thorn, on the under side of the breast. This is not of use to kill what they eat, or to fight their enemies. The beetle seizes his prey with his jaws, or with his fore feet. But if you try to hold him, then he draws his body back, and drives this thorn into your hand.
Water-beetles have flat pads on their feet, as water-spiders do. The hairs on these pads hold tiny bubbles of air.