Chap. X. HOMOPTEKA. 351 



in caires for the sake of their sods:, so that it must be 

 pleasing to the ears of some men. 22 The Cicadida3 

 usually sing during the day ; whilst the Fulgoridaa 

 appear to be night-songsters. The sound, according 

 to Landois, 23 who has recently studied the subject, is 

 produced by the vibration of the lips of the spiracles, 

 which are set into motion by a current of air emitted 

 from the tracheae. It is increased by a wonderfully 

 complex resounding apparatus, consisting of two cavi- 

 ties covered by scales. Hence the sound may truly 

 be called a voice. In the female the musical apparatus 

 is present, but very 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 sejrfemdecim of the United 

 States, says, 24 " the drums are now (June 6th and 7th, 

 " 1851) heard in all directions. This I believe to be the 

 " marital summons from the males. Standing in thick 

 " chestnut sprouts about as high as my head, where 

 " hundreds were around me, I observed the females 

 " coming around the drumming males." He adds, " this 

 " season (Aug. 1868) a dwarf pear-tree in my garden 

 " produced about fifty larvae of Cic. pruinosa; and I 

 " several times noticed the females to alight near a 

 " male while he was uttering his clanging notes." Fritz 

 Miiller writes to me from S. Brazil that he has often 

 listened to a musical contest between two or three 

 males of a Cicada, having a particularly loud voice, and 

 seated at a considerable distance from each other. As 



22 These particulars are taken from Westwood's ' Modern Class, of 

 Insects' v«l. ii. 1840, p. 422. See, also, on the Fulgoridse, Kirby and 

 Spciice, Introduce' vol. ii. p. 401. 



23 ' Zeitschrift fiir wissenschait. Zcolog.' B. xvii. 1867. s. 152-158. 



21 lam indebted to Mr. Walsh for having sent me this extract from 

 a ' Journal of the Doings of Cicada septemdecim,' by Dr. Hartman. 



