INSECT VARIETY. 227 



received action of the tymbals theoretically ; namely, that when 

 the insect sings the tymbals are alternately deflexed and relaxed, 

 and each tirne regain their shape with an elastic sonorous 

 spring, 



MM. Solier and Goureau in France, and Dr. Bennett in 

 Australia, have established the tymbals to be the source of the 

 sound by direct experiment, and they each state that when these 

 are torn the sound is diminished ; but if they be entirely removed 

 the song ceases, although a moment before of deafening intensity. 

 Carus reproduced the sound by moving the tendons with a pair 

 of forceps. 



But let us inquire experimentally what are the stimuli which 

 prompt the Cicadse to thus congregate and clamour. Can it be, 

 indeed, that insects without the threatening jaws of the cricket 

 and grasshopper kind, but having in lieu a slender rostrum to suck 

 the sap of trees, or as the Athenians thought the dewdrop, con- 

 sidered as a weaj)on unaggressive, are incited by kindred emotions 

 of love and jealousy to emit a music that is to be regarded as the 

 impulse to association ? The solution of this question lies in the 

 workings of the music, and on this subject Dr. Hartman, in speak- 

 ing of the well-known Cicada septemdecim of the United States, 

 whose name indicates an abundance every seventeenth year, says, 

 writing June 7th, 1851, ^^ The drums are now heard in all direc- 

 tions. This, I believe, is the marital summons from the males. 

 Standing in thick chestnut sprou.ts about as high as my head, where 

 hundreds were around me, I observed the females coming around 

 the drumming males. ^^ He again observes, in the month of 

 August, 1868, " This season a dwarf pear-tree in my garden pro- 

 duced about fifty larvse of another species (C. pruinoKa) ; and I 

 several times noticed the females to alight near a male who was 

 uttering his clanging notes. ^'' The females are, then, attracted 

 by the music of the males; there is reason also to infer the song 

 of the latter is stimulated by the principle of rivalry. " Fritz 

 Miiller," says Darwin,* " writes to me from South Brazil, that he 

 has listened to a musical contest between two or more males of a 

 cica.da having a particularly loud voice, and seated a considerable 

 distance from each other. As soon as the first had finished his 



* " Descent of Man," Vol. I., chap, x., p. 351. 



p 2 



