What, John? You know a water boatman that swims on its back?

That makes Nell laugh, and no wonder.

Yes, there is a little bug that swims on its back.

It is very much like the water boatman, and it has long paddles made of its queer hind legs.

Unlike the water boatman, however, its back is not flat but is shaped like the keel of a boat.

This being the case, it just turns over and swims with its keel-shaped back in the water.

It is sometimes called the back-swimmer, and most boys are well acquainted with it.

What do you think about catching it in your fingers, Ned?

Ah, you do not like to!

It has a very sharp beak for sucking the life out of other insects, and if you succeed in getting hold of it, it will stick that into your finger.

And my! how it does sting!

It is not an easy matter to catch it, however,—it is such a quick little rascal.