COCKROACHES, ETC. 151 



wing-covers, thus increasing the sound, which is still 

 further augmented by the dome-shaped wing-covers 

 acting as resonators. Dr. L. Peringuey x states that the 

 female of Palophus haworthi, a South African Phasmid, 

 when irritated suddenly opens with a loud tearing 

 sound the fan-like wings, which are too short to 

 support the body in flight, and at the same time jerks 

 the abdomen into the air. In one case the noise and 

 attitude were sufficiently alarming to put to flight a 

 cat that was cautiously investigating the Stick- Insect. 

 Stridulation amongst these defenceless insects is even 

 more of a " bluff " than in the case of the Mantidce ; 

 but if the bluff succeeds once in a thousand times its 

 value to the species might be incalculable. 



One and only one sub-family of the Phasmidce, the 

 Ascepasmince, has the claws of the feet toothed like 

 a comb, and it is difficult to know what advantages 

 these Phasmids have over the vast majority of other 

 species. Though I have kept some of them in cap- 

 tivity, I have failed to detect any particular use to 

 which the pectinate claws were applied. The claws 

 of insects differ in structure very considerably and 

 pectinate claws are found in many orders, but they 

 occur in a sporadic manner, some genera in the same 

 family possessing them whilst allied genera have the 

 ordinary simple type of claw. So far as we know the 

 structure of the claws bears very little if any relation 

 to the habits and modes of life of the insects, for 

 species with very similar habits have different kinds 

 of claws, and species with most dissimilar habits 

 often have claws of the same type. The fact of the 

 matter is that minute details of structures, which are 

 1 Proc. S. African Phil Soc., XIV. (1903-4), p. vii. 



