336 



ORTHOPTERA 



the three anterior of the four ganglia are but small, the terminal 

 one being much larger. 



The number of eggs deposited by a female mole-cricket is 

 large, varying, it is said, from 200 to 400. The mother watches 

 over them carefully, and when they are hatched, which occurs in 

 a period of from three to four weeks after their deposition, she 

 supplies the young with food till their first moult ; after this 

 occurs they disperse, and begin to form burrows for themselves. 



It has been said that the young are devoured by their parents, 

 and some writers have gone so far as to say that 90 per cent of 

 the progeny are thus disposed of. M. Decaux, who has paid 

 considerable attention to the economy of the mole-cricket, 1 acquits 

 the mother of such an offence, but admits that the male commits 

 it. The number of eggs in one nest is said to be about 300. 



The embryonic development of the mole-cricket has been 

 studied by Dohrn 2 and Korotneff, 3 and is considered by the 



former to be of great interest. The 

 tracheae connected with each stigma 

 remain isolated, while, according to 

 Korotneff, the development of the 

 alimentary canal is not completed 

 when the young mole - cricket is 

 hatched. Perhaps it may be this con- 

 dition of the digestive organs that 

 necessitates the unusual care the 

 mother bestows on her young. 



The genus Cylindrodes (Fig. 208, 

 C. kocJii) comprises some curious and 

 rare Insects of elongate, slender form. 

 They are natives of Australia, where 

 the first species known of the genus 

 FIG. 208. Cylindrodes kochi. wa s found in Melville Island by Major 



Australia. A, outline of the i n r> i i jv 



insect with five of the legs and Campbell, from whom we learn that 



the extremity of the body muti- these Insects burrOW in the Stems of 

 lated ; B, middle leg. (After , 



de Saussure.) plants, and are so destructive that he 



was unable to keep a single plant in 



his greenhouse on account of the. ravages of Cylindrodes 

 campbellii. The form of these Insects is beautifully adapted to 



1 Bull. Soc. cut. France, 1893, p. cccxli. 

 2 Zcitschr. wiss. Zool. xxiii. 1876, p. 122. 3 Ibid. xli. 1885, p. 570. 



