160 THE LOCUSTINA. 



for the destruction of the Locusts and their eggs. 

 The latter are deposited in the autumn in small sub- 

 terranean galleries, but in what manner the female 

 contrives to form these cavities for the reception 

 of her progeny does not appear to be very well 

 ascertained. The number of eggs varies from fifty 

 to one hundred, according to different authors; 

 the young Locusts are not developed until the com- 

 mencement of the warm season in the following year. 

 Nearly all the species of this tribe are capable of 

 producing the shrill chirping sound already alluded 

 to, and although its musical qualities are certainly 

 very limited, yet from the cheerful rural scenes with 

 which it is usually associated, I believe few people 

 with the least taste for the beauties of nature, can 

 stigmatise it as utterly disagreeable. The stridula- 

 tion, for voice it cannot be called, is produced by the 

 friction of the ridges of the inner surface of the thigh 

 against the elevated veins of the wing-cases, and as is 

 frequently the case amongst insects, as well as other 

 animals, it is only the male that is capable of giving 

 utterance to his feelings in song. The females are 

 always silent, and even the males of some species are 

 equally unable to produce any sound. Amongst 

 these the species of the genus Tetrix may be men- 

 tioned; they are the smallest insects of the tribe, and 

 are characterized by having the dorsal portion of the 

 prothorax produced backwards into a long roof-like 

 process, reaching usually beyond the apex of the 

 abdomen, and serving as a covering for the wings, 

 which would otherwise be left exposed in consequence 

 of the shortness of their natural protectors the elytra. 

 Several species of this genus are found in Britain, and 

 one of these, the Tetrix subulata, is very abundant. 



