210 WASP STUDIES AFIELD 



ping it, almost vertically, in the fork of the grass, then lift- 

 ing the other end to a slightly higher point. Thus, lifting 



FIG. 46. Sphex pictipennis carrying a small caterpillar. Natural size. 



the ends of the caterpillar alternately, she hoisted it out of 

 the chasm in the grass-thicket into which it had fallen, 

 exactly as a man, working alone, would hoist a heavy tim- 

 ber little by little. Our A. pictipennis always walks forward 

 with her prey beneath her, as did the Ammophilas ob- 

 served by the Peckhams, in contradiction to Westwood who 

 says that Ammophila, when she has captured her prey, 

 walks backward. 



In this point of her behavior we see the grossest error 

 in economy committed by Ammophila. She spends an 

 enormous amount of energy and time in trundling her 

 heavy caterpillar from a considerable distance, we know 

 not how far, and then dragging it all over the region in 

 the vicinity of her hole while locating the burrow. Since 

 she uses but one caterpillar, she might save all this needless 

 waste of time and energy by doing as Priononyx does, 

 digging the hole conveniently near to the prey after it has 

 been captured. The topography about the nest is usually 

 very similar in nature to the environment of the prey and 

 she seems not to be very particular about the location. To 

 be sure she has a preference for beaten paths and sunny 

 bald areas, but she as often uses any little bare spot be- 

 tween the weeds and grasses for her nesting-place. So why 

 should such a stupid habit persist, entailing frequent loss, 

 danger and expenditure of effort, while all of her other 

 methods of work have become so refined and highly devel- 

 oped? The only explanation that we have to offer is that 



