Now look down into the pond. I think you will see some water boatmen anchored near the bottom.
Yes, May, they cling by their front feet. Their hind pair of legs are rather odd-looking; they have a fringe of hairs on the inside.
John says their hind legs are modified to swim with.
Very good, John.
The hind legs are the oars that row these little boats about in the water.
But why are the little boats that have come to anchor down there moving their paddles so constantly?
Ah, yes; it is because they want fresh air to breathe.
You know there is always air in pond water, and they keep their paddles moving, so as to change the envelope of air that surrounds them.
They know what to do to take care of themselves, if they are nothing but little bugs.