INSECTS. 319 



Some species of Keduvidge make a stridulating noise; and 

 in the case of Pirates sfriduhis this is said* to be effected 

 by the movement of the neck within the pro-thoracic 

 cavity. According to Westring, Becliivius personatus also 

 stridulates. But I have no reason to suppose that this is a 

 sexual character, excepting that with non-social insects 

 there seems to be no use for sound-producing organs unless 

 it be as a sexual call. 



Homoptera. Every one who has wandered in a tropi- 

 cal forest must have been astonished at the din made 

 by the male Cicadae. The females are mute ; as the 

 Grecian poet Xenarchus says: ^' Happy the Cicadas live, 

 since they all have voiceless wives." The noise thus made 

 could be plainly heard on board the " Beagle/' when 

 anchored at a quarter of a mile from the shore of Brazil; 

 and Capt. Hancock says it can be heard at the distance of a 

 mile. The Greeks formerly kept, and the Chinese now 

 keep, these insects in cages for the sake of their song, so 

 that it must be pleasing to the ears of some men.f The 

 Cicadidae usually sing during the day, while the FulgoridaB 

 appear to be night-songsters. The sound, according to 

 Landois,J is produced by the vibration of the lips of the 

 spiracles, which are set in motion by a current of air 

 emitted from the trachae; but this view has lately been dis- 

 puted. Dr. Powell appears to have proved that it is pro- 

 duced by the vibration of a membrane set into action by a 

 special muscle. In the living insect, while stridulating, 

 this membrane can be seen, to vibrate; and in the dead 

 insect the proper sound is heard, if the muscle, when a little 

 dried and hardened, is pulled with the point of a pin. In 

 the female the whole complex musical apparatus is present, 

 but is much less developed than in the male, and is never 

 used for producing sound. 



With respect to the object of the music. Dr. Hartman, in 

 speaking of the Cicada septemdecim of the United States, 



* Westvvood, "Modern Class, of Insects," vol. ii, p. 473. 



f These particulars are taken from West wood's " Modern Class, of 

 Insects," vol. ii, 1840, p. 422. See also, on the Fulgoridae, Kirby 

 and Spence, " Introduct. ," vol. ii, p. 401. 



X "Zeitschrift fiir wissenschaft Zoolog.," B. xvii, 1867, ss. 152-158, 

 "Transact. New Zealand Institute," vol. v, 1873, p. 286, 



