WILLIAMS: HABITS OF WASPS. 229 



she clasped the under side of its thorax, her head toward the 

 caudal end of her leaping prey, her jaws applied to the latter's 

 body. She clung on tenaciously and soon quieted it with a 

 sting, administered somewhere on the locust's neck. After 

 this brief but strenuous period she took a short rest ; then pull- 

 ing her prey up a Russian thistle plant until the former was 

 about one and one-half inches above the ground, she set to work 

 locating a nesting site. This she soon found, only six inches 

 away. She commenced to dig at 4 :26 P. M. She visited her 

 prey on the Russian thistle three times before the hole was 

 excavated, which was at 5 P. M. Finally grabbing the Aulocara 

 by the antennse, she dragged it to just before her burrow, 

 into which she backed. A little Tachina fly which had been 

 carefully watching the wasp while digging her tunnel, and 

 even following her on her occasional tours of inspection to the 

 weed where the Aulocara lay, now availed herself of the op- 

 portunity presented her by the wasp's disappearance in the 

 tunnel to viviposit at the base of the locust's elytron. Hardly 

 was the parasite's work accomplished when Prwnonyx, emerg- 

 ing, seized her victim by the antennae and dragged it within. 

 She remained inside long enough to lay her egg on the locust. 

 She filled her burrow as in the first instance, and completed 

 her work at 5 :25 P. M., or one hour and fifteen minutes after 

 she had filled up her first nest. Like the first tunnel, this one 

 was in a depression where the soil crust had been broken. The 

 wasp was caught and her nest dug up. This sloped quite 

 steeply up to the subhorizontal cell ; here, on its venter, lay the 

 locust, the rather long, curved wasp egg {E. fig. 6) secured in 

 the membrane just anterior to one of the hind femora and 

 immediately dorsad the hind coxa. This position is always 

 chosen by this wasp. The hole was of rather large bore and 

 measured two inches deep by two and one-half inches long. 



These wasps sometimes occur in small, ill-defined colonies, 

 and while at work at their tunnels could often be located by 

 reason of the squeaky buzz which they emitted from time to 

 time, and which was plainly audible from a distance of a dozen 

 feet. In Morton county, where the soil was rather wet and 

 heavy from recent heavy rains, the wasp used her jaws to a 

 large extent and brought out considerable loads of earth, which 

 she held between her open jaws and her fore legs. She carried 

 out as many as four or five loads per minute. The tunnels are 



3-Univ. Sci. Bull.. Vol. VHI, No. 6. 



