The Return to the Nest 317 



herself. The places which she has already 

 tested and swept twenty times over she returns 

 to test and sweep again, unable to bring herself 

 to leave her narrow radius, so obstinate is her 

 conviction that the door must be here and not 

 elsewhere. Several times in succession I push 

 her gently with a straw to some other point. 

 She will not be put off : she returns straightway 

 to the place where her door once stood. At 

 rare intervals the gallery, now an open trench, 

 seems to attract her attention, though very 

 faintly. The Bembex takes a few steps towards 

 it, still raking, and then goes back to the entrance. 

 Twice or thrice I see her run the whole length 

 of the conduit and reach the blind alley, the 

 abode of her grub ; here she gives a few care- 

 less strokes of the rake and hurries back to 

 the spot where the entrance used to be, con- 

 tinuing her quest there with a persistency that 

 ends by wearying mine. More than an hour has 

 passed and the stubborn Wasp is still pursuing 

 her search on the site of the vanished doorway. 

 What will happen when the larva is present ? 

 This is the next aspect of the question. To 

 continue the experiment with the same Bembex 

 would not have given me the positive evidence 

 which I wanted, for the insect, rendered more 

 obstinate by its vain quest, seemed to me now 

 obsessed by a fixed idea, which would certainly 



