346 



SEXUAL SELECTION. 



[Part II. 



In the last and third Family, namely, the AcridiMae 

 or grasshoppers, the stridulation is produced in a very 

 different manner, and is not so shrill, according to Dr. 

 Scudder as in the preceding Families. The inner surface 

 of the femur (fig. 13, r) is furnished with a longitudinal 

 row of minute, elegant, lancet-shaped, elastic teeth, from 

 85 to 93 in number; 37 and these are scraped across the 

 sharp, projecting nervures on the wing-covers, which are 

 thus made to vibrate and resound. Harris 31 says that 



when one of the males 

 begins to play, he first 

 "bends the shank of 

 the hind-leg beneath the 

 thigh, Where it is lodged 

 in a furrow designed to 

 receive it, and then draws 

 the leg briskly up and 

 down. He does not play 

 both fiddles together, but 

 alternately first upon one 

 and then on the other." 



Fig. 13.— Hind-!egof Stenobothrus pratoram: T n mnrlv <mpr>ip<i thp hnsp 

 r, the Btridu&ting rid^e ; lower figure, in man y Species tne VdhV 



Sited (from lTuSLT ridge ' much mag " of the abdomen is hol- 

 lowed out into a great 

 cavity which is believed to act as a resounding-board. In 

 Pneumora (fig. 14), a South African genus belonging to this 

 same family, we meet with a new and remarkable modifi- 

 cation : in the males a small notched ridge projects ob- 

 liquely from each side of the abdomen, against which the 

 hind femora are rubbed. 39 As the male is furnished with 



the Platyphyllum concavum, " when captured, makes a feeble grating 

 noise by shuffling her wing-covers together." 

 31 Landois, ibid. s. 113. 



38 'Insects of New England,' 1842, p. 133. 



39 Westwood, ' Modern Classification,' vol. i. p. 462. 



