The peculiar sounds made by different insects, though usually known as insect music, are probably far from musical in the opinions of those who listen to it with dread. Many superstitious people have firm belief in dire warnings concerning certain calamities which "insect music" portends.
For instance we are told that the "deathwatch" is a popular name applied to certain beetles which bore into the walls and floors of old houses. They make a ticking sound by standing on their hind legs and knocking their heads against the wood quickly and forcibly. Many superstitions have been entertained respecting the noise produced by these insects, which is sometimes imagined to be a warning of death.
There are many insects, however, which produce sound decidedly musical; and many such instances have been enumerated. Everybody is familiar with the music of the katydid. Here it is the male that has the voice. At the base of each wing cover is a thin membranous plate. He elevates the wing covers, and rubs the two plates together. If you could rub your shoulder blades together you could imitate the operation very nicely.
Certain grasshoppers make a sound when flying that is like a watchman's rattle clacketty-clack, very rapidly repeated. There are also some moths and butterflies which have voices.
The "death's-head" moth makes a noise when frightened that strikingly resembles the crying of a young baby. How it is produced is not known, though volumes have been written on the subject.
The "mourning cloak" butterfly a dark species with a light border in its wings makes a cry of alarm by rubbing its wings together.
The katydids, crickets, grasshoppers and other musical insects are all exaggerated in the tropics, assuming giant form. Thus their cries are proportionately louder.
There is an East Indian cicada which makes a remarkably loud noise. It is called by the natives "dundub," which means drum. From this name comes that of the genus which is known as Dundubia. This is one of the few scientific terms from Sanskrit.
Entomologists have succeeded in recording the cries of many insects by the ordinary system of musical notation. But this method does not show the actual pitch, which is usually several octaves above the staff. It merely serves to express the musical intervals.
It is known with reasonable certainty that many insects have voices so highly pitched that they cannot be heard with the human ear. One evidence of this fact is that some people can distinguish cries of insects which are not audible to others. But even if there are a few notes lost to many of us, there is enough insect music to prove vastly entertaining to those who take interest in the insect world, and the peculiar methods of its inhabitants in communicating with each other.