An Unknown Sense 



sense about which entomologists are not ade- 

 quately informed. Where is its seat? In 

 the antennae, we are told. Those fine, quiv- 

 ering stalks would seem fairly well-suited to 

 be put in motion under the impulse of sound. 

 In that case, the Ammophila, exploring the 

 region with her antennae, would be warned of 

 the presence of the Grey Worm by a slight 

 noise coming up from the ground, the noise 

 of the mandibles nibbling a root, the noise of 

 the caterpillar wriggling its hind-quarters. 

 What a faint sound and how difficult to trans- 

 mit through the spongy cushion of the earth ! 



It is less than faint, it is non-existent. 

 The Grey Worm is nocturnal in its habits. 

 By day it skulks in its lair and does not stir. 

 It does not nibble either; at least, the Grey 

 Worms which I unearthed upon the Wasp's 

 indications were nibbling nothing, for the 

 very simple reason that they had nothing to 

 nibble. They were completely motionless 

 and therefore silent in a layer of earth de- 

 void of roots. The sense of hearing must 

 be rejected with that of smell. 



The question recurs, more abstruse than 



ever. How does the Ammophila go to work 



to recognize the spot beneath which the Grey 



Worm lies? The antennae are, beyond a 



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