346 



SEXUAL SELECTION. 



[Part IL 



In the last and third Family, namely, the Acridiidse 

 or o-rasshoppcrs, the stridulation is produced in a very 

 diftercnt nuuiner, 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;" and these are scraped across the 

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

 thus made to vibrate and resound. Harris" 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-lcs^ofStenobothnispratorum: T„ ,vio,i-tr cnp^^pa thp bnsp 

 r, the strululating ridiic; loWer fl-ure, "^ many SpCCieS tnc oase 



the teeth, forming: the ridge, much mag- f.f f]-,p. ohdonipn is hol- 

 nilied (from Landois). ^ OT. int auuoiiitu it> uui 



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. '° As the male is furnished with 



the Platiiphyllum 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, ' Modem Classification,' vol. i. p. 462. 



