[Illustration]
Probably it was the longhorned grasshoppers that Charlie saw so many of
in the meadow.
Look, next time, Charlie, and see if the swarms that start up before you
have not long, slender antennæ.
See, here is one.
Its antennæ are like threads, and they are longer than its body.
If you were to look at its tarsus, you would find it had four joints
instead of three.
Otherwise, the longhorned, or meadow grasshoppers are very much like the
locusts, or shorthorned grasshoppers.
John says he thinks the meadow grasshoppers are more slender and
delicate in shape.
That is true, as a rule, though there are some species of the locusts
that are as slender as the longhorned grasshoppers.
But there is one thing about these longhorned fellows that will amuse
you.
Some of them have ears on their front legs!
It is not uncommon for insects to have hearing organs on their front
legs.
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.
[Illustration]
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 antennæ.
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 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.
[Illustration]
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?
[Illustration]