Page:Insect Literature by Lafcadio Hearn.djvu/158

Rh can show you that, under normal conditions of temperature and environment, the number of light-pulsations produced by one species of Japanese firefly averages twenty-six per minute; and that the rate suddenly rises to sixty-three per minute, if the insect be frightened by seizure. Also he can prove to you that another and smaller kind of firefly, when taken in the hand, will increase the number of its light-pulsings to upward of two hundred per minute. He suggests that the light may be of some protective value to the insect,—like the "warning colours" of sundry nauseous caterpillars and butterflies,—because the firefly has a very bitter taste, and birds appear to find it unpalatable. (Frogs, he has observed, do not mind the bad taste: they fill their cold bellies with fireflies till the light shines through them, much as the light of a candle-flame will glow through a porcelain jar.) But whether of protective value or not, the tiny dynamo would seem to be used in a variety of ways,—as a phototelegraph, for example. As other insects converse by sound or by touch, the firefly utters its emotion in luminous pulsings: its speech is a language of light………I am only giving yon some hints about the character of the professors lectures, which are never merely technical. And for the best 註