Chap. X. 



ORTHOPTERA. 



357 



u 



Fig. 13. Hind-leg of Stenobothrus pratorura: 

 r, the striduiating ridge ; lower figure, the 

 teeth, forming the ridge, much magnified 

 (from Landois). 



across the sharp, projecting nervures on the wing-covers, 



which are thus made to vibrate and resound. Harris 3 



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 de- 



" signed to receive it, 



" and then draws the lee 



a 



briskly up and down. 



He does not play both 

 " fiddles together, but al- 

 " ternately first upon one 

 " and then on the other." 

 In many species, the base 

 of the abdomen is hollowed out into a great cavity 

 which is believed to act as a resounding board. In 

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

 this same family, we meet with a new and remarkable 

 modification : in the males a small notched ridge pro- 

 jects obliquely from each side of the abdomen, against 

 which the hind femora are rubbed. 39 As the male is 

 furnished with wings, the female being wingless, it is 

 remarkable that the thighs are not rubbed in the usual 

 manner against the wing-covers ; but this may perhaps 

 be accounted for by the unusually small size of the hind- 

 legs. I have not been able to examine the inner 

 surface of the thighs, which, judging from analogy, 

 would be finely serrated. The species of Pneumora 

 have been more profoundly modified for the sake of 

 stridulation than any other orthopterous insect; for 



3S 'Insects of New England,' 1842, p. 133. 



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



