Genera and Species o/BlattiJse. 1G5 



latter genus have the pronotum well adapted for digging, but 

 others have not, and it would be of the greatest interest to 

 learn if tlie habits of the species vary in correlation with the 

 form of the pronotum. 



Bantua is intermediate in structure between Cyrtotria and 

 Derocalymma ; some specimens collected by Dr. LongstafF in 

 S. Africa were taken from beneath a log, which means, I 

 expect, that they were lurking in the rubbish immediately 

 surrounding the log, as they are not adapted, like JJero- 

 calymma^ for life beneath a heavy body, judging by their 

 facies. 



Finally, the question arises, has Derocahjmma originated 

 from a form like Filemn, passing in the course of its evolution 

 through a Bantua-Wka stage? One is tempted to answer in 

 the artirmative, for adaptation to life beneath stones could 

 have been brought about by mere flattening of a generalized 

 type of cockroach with a simple form of pronotum, as has 

 indeed occurred in the Australian genus Oniscosoma, super- 

 ficially similar to Derucalymma^ but structurally widely 

 different. The highly modified pronotum of Derocahjmma 

 has resulted from the flattening not of a simple form of: pro- 

 notum, but of a complex form with lateral bands ; the lateral 

 bands in Pilema are the most essential parts of the exca- 

 vating organ, the pronotum ; but they can serve no useful 

 purpose in species that do not burrow into the ground, and 

 the manner of their modification in response to a different 

 habit of life is shown in the genus Bantua, and especially in 

 the new species of that genus described below, the final step 

 in the process being exhibited by Derocalymma. 



Cyrtotria, Saussure and Zehntner (ncc StSl), Rev. Suisse Zool. iii. p. 28 

 (1895). 



Differs from Pilema^ Sauss., and Cyrtotria, Stal, in the 

 form of the pronotum, the lateral bands being bent under the 

 disk and forming an acute angle with it; the margin of the 

 pronotal disk forms the outer margin of the pronotum. In 

 the female the posterior angles of the pronotum are more or 

 less produced backwards. Differs from the genus Dero- 

 calymma, Hurm., by the less complete bending under of the 

 lateral bands of the pronotum, by the membranous tegmina 

 of the male, and the backwurtlly [)roduced posterior angles of 

 the pronotum in the female. 



Type of genus. Perisphceria dispar, Burm. 



