Chap. X. 
ORTHOPTERA. 
355 
subordinate modification ; for the wing-covers are greatly 
reduced in size, but “ the posterior part of the pro-thorax 
“ is elevated into a kind of dome over the wing-covers, 
“ and which has probably the effect of increasing the 
“ sound .” 34 
We thus see that the musical apparatus is more 
differentiated or specialised in the Locustid®, which 
include I believe the most powerful performers in 
t'le Order, than in the Achctidse, in which both wing- 
covers have the same structure and the same function . 35 
dj&ndois, however, detected in one ot the Locustidse, 
Namely in Oecticus, a short and narrow row ot small 
si Westwood, ‘ Modern Class, of Insects,’ vol. i. p. 453. 
35 Landois, ibid. s. 121, 122. 
