112 WASP STUDIES AFIELD 



the hole behind her. But at this interesting climax the boys 

 came romping across the diamond ready for their game, so 

 we were obliged to relinquish the field to them. 



For about seven days we had kept our eyes on another 

 burrow and had known that activities were going on in- 

 side it, and a few times we had caught sight of the female 

 or had seen some fresh earth thrown out. On September 

 24 we opened the hole and found its entire length to be about 

 twelve inches. It followed a somewhat irregular slope of 

 approximately thirty degrees, so the end was five inches 

 beneath the surface of the ground. The mother was in the 

 burrow. Near the terminus was a short branch gallery or 

 neck, leading off at a right angle from the main channel ; 

 this led to a chamber which was oval and a trifle more than 

 a half-inch long. This neck was snugly filled with soil, and 

 the chamber contained a white pupal case and some heads 

 and wings of bees. Another burrow of an identical general 

 plan, although with the main channel a little more crooked 

 (fig. 29), leads us to think that the mother Philanthus digs 

 a long main burrow, then makes, near the end of this, a 

 branch with a pocket which she provisions and seals, and 

 that she then proceeds to extend the main burrow further, 

 with a view to making more cells on the sides. If this 

 species uses one burrow for several young, she is more eco- 

 nomical than BembLr, which probably digs a new burrow 

 for each larva. 



Another of these nests was discovered on July 23. It 

 pierced the side wall of a little depression, and a large quan- 

 tity of loose earth lay scattered beneath it. One of us 

 chanced to be near when the Philanthus came to her'hole at 

 8:30 a, m., brushed out the loose dirt with her forelegs, 

 kicking it backwards under her body in a way very similar 

 to Bembix, and darted into the hole. Once inside, she 



