342 



SEXUAL SELECTION. 



[Part II. 



it can be heard during the night at the distance of a 

 mile ; 25 and that made by certain species is not unmusical 

 even' to the human ear, so that the Indians on the Ama- 

 zons keep them hi wicker cages. All observers agree that 

 the sounds serve either to call or excite the mute females. 

 But it has been noticed 26 that the male migratory locust 

 of Russia (one of the Acridiidae), while coupled with the 

 female, stridulates from anger or jealousy when ap- 

 proached 'by another male. The house-cricket when sur- 

 prised at night uses its voice to warn its fellows. 27 In 

 North America the Katy-did (Platyphyllum concavum, 



one of the Locustidse) is 



described 28 as mounting 

 on the upper branches of a 

 tree, and in the evening be- 

 ginning his noisy babble, 

 while rival notes issue from 

 the neighboring trees, and 

 the groves resound with the 

 call of Katy-did -she -did 

 the live-long night." Mr. 

 Bates, in speaking of the 

 European field-cricket (one 

 of the Achetidae), says: 

 "The male has been ob- 

 served to place itself in the 

 evening; at the entrance of 

 its burrow, and stridulate 

 until a female approaches, when the louder notes are 

 succeeded by a more subdued tone, while the success- 

 ful musician caresses with his antennae the mate he has 



25 L. Guilding, ' Transact. Linn. Soc.' vol. xv. p. 154. 



26 Koppen, as quoted in the 'Zoological Record,' for 1867, p. 460. 



27 Gilbert White, ' Nat. Hist, of Selborne,' vol. ii. 1825, p. 262. 

 18 Harris, 'Insects of New England,' 1842, p. 128. 



Fig. 10.— Gryllus campestris (from Lan- 

 dois). 



Rteht-hand figure, under Bide of part of 

 the wing-nervur?, much magnified, 

 showing the teeth, st. 



Left-hand figure, upper surface of wing- 

 cover, with the projecting, smooth ner- 

 vure, r, across which the teeth (st) are 

 scraped. 



