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 antennæ, 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.