Part 31

You know what an ear is. It is something to hear with. The hearing part of our own ears is way inside, out of sight.

The outer part of the ear, that we can take hold of, is only a sort of funnel to gather up the sound, and we could still hear if this part of our ears were cut off.

Way back inside the ear is a little curtain, or eardrum, made of a thin membrane.

When sounds enter the ear they cause the eardrum to tremble or vibrate, and this excites the nerve of hearing that is behind the eardrum.

Now some grasshoppers have a little flat membrane on the tibia of each front leg. It is an eardrum. Behind it is the nerve of hearing. When sounds strike the eardrum it vibrates and excites the nerve of hearing.

So you see the insects have ears, though they have no funnel-like outsides to them.

So, after all, there isn't so very much difference between the way the grasshoppers hear, and the way we hear, although they do hear with their legs.

Yes, Ned, it is about the same thing when they hear with sensitive spots on their antennae.

The sounds strike the sensitive spots, which are tiny eardrums, and cause the nerves that come to them to hear.

You see, after all, an ear is only a membrane able to vibrate when sounds strike it and a nerve sensitive to those sounds.

It does not matter much where the ear is located. Our ears are on either side of our head, and so are the ears of all the higher animals.

But the ears of the insects are more useful to them when on the antennae, or the legs, or some have them on the abdomen. An ear is an ear wherever it happens to be, and the insects hear well enough with theirs.

In many species of the longhorned grasshoppers, the male has a curious musical instrument on his wing covers, close to where they grow from the body.

Little Mr. Grasshopper sings to his lady-love by rubbing the upper parts of the wing covers together. You see the round places at X,--those are the modified parts of the wing cover, by means of which he can make his music.

What is that, May? Your grasshopper has a long sword at the end of its body?

Yes, that is its ovipositor. Ovipositor means "egg-placer."

With this long, sharp ovipositor the grasshopper can roughen the bark of twigs or make holes in the stems of plants or in the earth.

Then the eggs are guided down through the long ovipositor to the place prepared for them, and fastened there by a gummy substance.

Only the female grasshoppers have the long, sword-shaped ovipositor.

The ovipositor of the locust is not long and sword-like.

It is short, but it is strong and sharp, and you remember how the locust uses it to dig with.

Yes, indeed, Mollie, there are a great many species of locusts and grasshoppers, and some of them are very beautiful.

In hot countries they sometimes grow to an enormous size.

May is asking why they make molasses.

No, Ned, of course it isn't molasses. Children call it molasses because it looks like it.

Now, May, where does it make its molasses?

In its mouth, you say, and then it spits it out on your finger.

What? You don't like its old molasses on your finger?