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, 
c: and which has probably the effect of increasing the 
“ sound.” 34 
Fig. 12. Chlorocoelus Tanana (from Bates), a, b. Lobes of opposite wing-covers. 
We thus see that the musical apparatus is more 
differentiated or specialised in the Locustidae, which 
includes I believe the most powerful performers in 
the Order, than in the Achetidae, in which both wing- 
covers have the same structure and the same function . 35 
Landois, however, detected in one of the Locustidae, 
namely in Decticus, a short and narrow row of small 
34 Westwood, ‘ Modern Class, of Insects,’ vol. i. p. 453. 
35 Landois, ibid. s. 121, 122. 
2 a 2 
