Page:Popular Science Monthly Volume 39.djvu/699

ring, and which, when the vocal cords begin to vibrate, vibrates with them and serves as a resonance apparatus. Although there is no real voice, which with us is inseparable from a mouth, we can say that the cicada comes nearest among insects to having such a gift There is a curious relative of our cicada in America, which in its larval condition exhibits a phenomenon that nothing else is like. The larva lives in that form fully seventeen years under ground before it assumes the shape of a perfect insect. It has been called by the characteristic name of the seventeen-year locust. The voice of this locust was heard on board the Beagle, in which Darwin made his famous voyage, an English mile off. Its song is essentially a trill of the treble E with D sharp, then a run down the chromatic scale and rapidly up again, about such a strain as one would play if he slipped his finger up and down the string of a violin while drawing the bow over it. The musical reader may gain from the following an idea of the talent as a composer, and of the song of this locust:

With most musical insects there is no special apparatus for the production of tones. They simply combine the useful with the agreeable. The wings that bear them through the air also make the sound-waves. The only remarkable thing is, that the flying-tones thus produced are so different in single kind. The wings of the bee, for example, vibrate four hundred and forty times in a second—the same number of vibrations as in our normal tone; it is the music-master, and is the cleverest and best esteemed of insects. In other bees, as the female bumble-bee, the wings vibrate eight hundred and seventy times in a second, and sound the treble A, an octave higher than the bee. Marey, who has succeeded in photographing the flight of birds, has also found an ingenious method of determining the number of vibrations of insects' wings. He fixed a fly so that the extreme tip of its wing touched a soot-blackened cylinder, which could be turned by clock-work upon its axis. Every stroke of the wing made a faint but perceptible mark, by means of which Marey was able to deter-mine that the fly made three hundred and thirty wing-beats in a second.

As we sit at night by the lamp, there arises suddenly a loud humming tone, alternately swelling to considerable strength and diminishing till it is barely heard, until the musician, a large blue-bottle fly, to our annoyance darts humming against our cheek or hand, or precipitates himself into the lamp. Every reader has