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CH. Ill] THE COCKROACH 87 



The common Currant Moth (Abraxas grossulariata) is 

 a notable malingerer, and will feign death even after 

 decapitation. In 1895 I decapitated a specimen that was 

 feigning death, and was able to keep it in a responsive 

 condition for two days, during which period any stimulus, 

 such as touching or pinching, induced a repetition of the 

 death-feigning: a strong stimulus was followed by a 

 prolonged, and a weak one by a more brief quiescence. 

 Eventually a weak fluttering movement set in for some 

 hours, followed by death. 



In this case it is clear that the sensory stimulus 

 received by the surface of the body caused inhibitory 

 impulses to arise reflexly in the ganglia of the ventral 

 nerve chain and prevent all movement of the locomotor 

 muscles. Areas of the wings which had become denuded 

 of scales showed a marked diminution in sensibility, 

 thereby indicating that the scales are tactile organs. 

 The scales of Lepidoptera are merely highly modified 

 representatives of the hairs or bristles that are frequent 

 on the limbs and bodies of other insects where they 

 function as organs of touch. 



This sense is in the cockroach and in all insects very 

 highly developed in the antennae and in the palps of the 

 1st maxillae and labium. The antennas and the palps are 

 kept constantly flickering over the surface on which the 

 cockroach is travelling. From time to time the former 

 are waved in the air, in a manner suggestive of their 

 possessing also the sense of smell, as indeed is almost 

 certainly the case, some 39,000 sensory rod-like nerve 

 endings being situated in each antenna of the male. The 



