THE SAND-LOVING AMMOPHILA 223 



other Hymenoptera, by place-memory. In contrast to the 

 nicety with which they often return to their holes with the 

 caterpillars, witness their difficulty in regaining their prey 

 when they are compelled suddenly to leave it. Recently we 

 suddenly came thus upon one as she was carrying her prey 

 across the low grass, so that we could not check our footsteps 

 in time and she abruptly flew away. We drew back and, 

 though we watched her search for an hour and a half, she 

 never succeeded in regaining it. Sometimes she was very 

 near to it, but seemed entirely unaware of this, and finally 

 she gave up the search. 



Another Ammophila left her hole as we came by, but not 

 in apparent alarm. She seemed in search of something and 

 presently picked up a pellet, but she had walked three feet 

 from her hole in her wandering search for a suitable one. 

 During her absence, we marked the location of the nest in 

 the usual method, by pinning a bit of paper near it. This 

 evidently confused her when she returned; she spent five 

 minutes walking to and fro within a radius of a foot of her 

 hole, and many times within an inch of it, without perceiv- 

 ing it. She even walked across the opening three times with- 

 out recognizing it as her own. On the fourth crossing, she 

 paused and was about to the drop the pellet when she seemed 

 to change her mind; she left the pellet an inch from the hole 

 while she first ventured into the burrow with an inquiring 

 air an unusual performance; then she promptly re- 

 appeared and dropped this pellet and another into the hole, 

 and then went off in the same direction as before in quest 

 of another. The earth here was smooth and sun-baked, and 

 she had to go long distances for clods. She brought the 

 next one from a distance of seven yards and returned, 

 readily enough, to the general region of her nest, but here, 

 within a few inches of her burrow, she sought nervously, for 

 a half -hour, for her hole, sometimes carrying her property 



