Chap. X. 
QRTHOPTERA. 
357 
Fig. 13. 
Hind-leg of Stenobothrus pratornm : 
r, the stridulating 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 38 
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 leg 
“ 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 
38 ‘ Insects of New England,’ 1842, p. 133. 
39 Westwood, ‘ Modem Classification,’ vol. i. p. 462. ] 
