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 



Fig. 12. (Jblorocoilus Tanana (from Bates), a, b. Lobes of opposite wing-covers. 



We thus see that the musical apparatus is more 

 differentiated or specialised in the Locustidse, which 

 includes I believe the most powerful performers in 

 the Order, than in the Achetidse, in which both wing- 

 covers have the same structure and the same function. 35 

 Landois, however, detected in one of the Locustidse, 

 namelv in Decticus, a short and narrow row of small 



31 Westwood, ' Modern Cla&s. of Insects,' vol. i. p. 453. 

 35 Landois, ibid. s. 121, 122. 



2 a 2 



