266 INSECT LIFE 



XIX 



in a cul-de-sac where lay the larva amid its 

 food. 



The dwelling was uncovered in full sunshine ; 

 how would the mother behave on her return ? Let 

 us consider the question scientifically. The observer 

 may be greatly embarrassed : what I have already 

 seen leads me to expect it. The mother's impulse 

 is to bring food to her larva, but to reach this larva 

 she must first find the door. Grub and entrance 

 are the points which appear to deserve being separ- 

 ately examined ; therefore I take away grub and 

 food, and the end of the passage is cleared. There is 

 nothing more to do but arm one's self with patience. 



At last the Bembex arrives and makes straight 

 for her absent door, only the threshold of which 

 remains. There for a good hour did I see her dig, 

 sweep the surface, send the sand flying, and persist, 

 not in making a new gallery, but in seeking the 

 loose sand barrier which should yield to the 

 mere pressure of her head and let her pass easily. 

 Instead of loose materials she finds firm soil not 

 yet disturbed. Warned by this resistance she limits 

 her efforts to exploring the surface, always close to 

 where the door should be, only allowing herself to 

 deviate a few inches. She returns to sound and 

 sweep places already sounded and swept some twenty 

 times, unable to leave her narrow circle, so obsti- 

 nately convinced is she that the door must be there 

 and nowhere else. With a straw I pushed her 

 gently and repeatedly to another point. She would 

 have none of it, and came back at once to where 

 the door ought to have been. Now and then the 

 gallery, turned into a semi-canal, appeared to attract 



