294 KANSAS UNIVERSITY SCIENCE BULLETIN. 



I sometimes collected males of this species on sand or gravel 

 bars by streams, where they were apparently sunning them- 

 selves. They were never abundant there, however, as was 

 0. arvensis. 



0. dorsalis never seemed to have any difficulty in finding h(n- 

 way to her burrow after a trip to the field. Usually she flew 

 directly to it; I never saw her do otherwise when she was re- 

 turning from the field with prey. At times when she returned 

 from the field unladen, I have seen her pause at another bur- 

 row in the colony. This action may have been prompted by 

 curiosity instead of being a mistake in location. I have noted 

 a number of these wasps make a locality study above a spot 

 selected for a nesting site. 



Although not generally sensitive to observation, 0. dorsalis 

 was more responsive to changes in the surroundings of her 

 burrow than was O. papagorum. A few marks with a knife, to 

 assist in locating a nest at a later time, seemed to disturb one 

 wasp considerably. On her return to the nest she made a pro- 

 longed observation fiight of irregular circles above her nest, 

 while she had been in the habit of alighting without any hesita- 

 tion. On another occasion I mutilated slightly the entrance to 

 a burrow. Upon the wasp's return she circled around the 

 burrow a few times and then alighted about two inches from 

 the entrance. She flew away and returned in about a minute 

 and repeated the observation performance. Again she flew 

 away and returned without entering. This time she appar- 

 ently deserted the nest. 



Pterochilus 5-faciatus Say. 



In the middle of a sandy road, beside the Saline river, Mr. 

 Williams and Mr. Mallory noticed a large eumenid dragging 

 a long caterpillar under her body. I was only a short distance 

 away, and they called me to see it. The eumenid entered a 

 thicket of Chenepodium, dragged the caterpillar to a large 

 hole about two feet from the roadside, and entered it quickly, 

 still dragging the caterpillar under her body. 



We left Pterochilus 5-faciatus there — for she was so identi- 

 fied later — and continued on our way to locate and pitch a 

 temporary camp. This observation was made at 12:30 P. M., 

 July 24. 



I returned to the nesting site at 3 :40 p. M., and Pterochilus 

 appeared twenty-five minutes later. She brought nothing, biT 



