Part 44

Now, there is a little row of holes or pores along each side of the abdomen of the insect.

These are the breathing pores. No, May, the insects do not breathe through their mouths, they breathe through their sides.

You can see the breathing pores, or spiracles, as they are called, very plainly in many insects.

You can see them on the abdomen of the locust, and in some caterpillars they are bright-colored spots.

There are spiracles on the sides of the thorax, too, but they do not show so plainly as those on the abdomen.

The spiracles open into air tubes that carry air to the blood of the insect.

If you watch a grasshopper or a bee, you can plainly see it breathe. The abdomen moves in the bee as though it were panting. These movements of the abdomen cause the air to go in and out. All insects move their abdomens to send the air in and out, but it does not show plainly in all of them, for, though insects need air, some of them can get along with very little.

Yes, John, insects have blood. It is not just like our blood, but still it is blood.

It is not generally red in color, though sometimes it is reddish, and sometimes it is brown, or violet, or even bright green.

Yes, that seems strange to you, but you remember how ears are ears, and serve to hear with, no matter where on the body of the creature they are located. So blood is blood, and serves the purpose of blood, no matter what its color. The blood of some insects has a very bad odor, and in the case of certain beetles, when they are disturbed, this foul-smelling liquid oozes out of the joints of the legs.

Yes, Mabel, it is probably used, like the "molasses" of other little friends we know, to repel enemies.

But to return to breathing. Some larvae breathe by gills, and do not have spiracles until they are grown up, but all grown-up insects breathe by spiracles.

Yes, John, the larvae of the dragon flies and May flies breathe with gills.

I thought you would remember that.

The water boatman breathes by spiracles, and carries his supply of air with him. All grown-up bugs breathe by spiracles.

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.

When winter comes, they go down to the bottom of the pond and bury themselves in the mud. They lie there without moving or breathing until spring, when out they come, as lively as ever.

Yes, certain other animals pass the winter in this way; the bears, for instance, find a snug den and sleep all through the coldest winter weather. We call this winter sleep of animals hibernation, and many of the insects hibernate.

Yes, Ned, hibernating animals can get on with very little air; they sometimes seem to need none at all, and they take no food.

May wants to know what these queer water boatmen eat.