's hand, the electrical shocks which seem to go up
the arm help the belief in this idea. To many of us the song of the
cicada--softened by distance--will ever be pleasant on account of its
associations. When one attempts to picture a hot August day in a hay-field
or along a dusty road, the drowsy _zee-ing_ of this insect, growing louder
and more accelerated and then as gradually dying away, is a focus for the
mind's eye, around which the other details instantly group themselves.

The apparatus for producing this sound is one of the most complex in all
the animal kingdom. In brief, it consists of two external doors, capable
of being partly opened, and three internal membranes, to one of which is
attached a vibrating muscle, which, put in motion, sets all the others
vibrating in unison.

We attach a great deal of importance to the fact of being educated to the
appreciation of the highest class of music. We applaud our Paderewski, and
year after year are awed and delighted with wonderful operatic music, yet
seldom is the _limitation_ of human perception of musical sounds
considered.

If we wish to appreciate the limits within which the human ear is capable
of distinguishing sounds, we should sit down in a meadow, some hot
midsummer day, and listen to the subdued running murmur of the myriads of
insects. Many are very distinct to our ears and we have little trouble in
tracing them to their source. Such are crickets and grasshoppers, which
fiddle and rasp their roughened hind legs against their wings. Some
butterflies have the power of making a sharp crackling sound by means of
hooks on the wings. The katydid, so annoying to some in its persistent
ditty, so full of reminiscences to others of us, is a large, green,
fiddling grasshopper.

Another sound which is typical of summer is the hum of insects' wings,
sometimes, as near a beehive, rising to a subdued roar. The higher,
thinner song of the mosquito's wings is unfortunately familiar to us, and
we must remember that the varying tone of the hum of each species may be
of the greatest importance to it as a means of recognition. Many beetles
have a projecting horn on the under side of the body which they can snap
against another projection, and by this means call their lady-loves,
literally "playing the bones" in their minstrel serenade.

Although we can readily distinguish the sounds which these insects
produce, yet there are hundreds of small creatures, and even large one