278 KANSAS UNIVERSITY SCIENCE BULLETIN. 



ing a caterpillar into one of these nests. I could not climb up 

 to the place, so I took the nest, wasp and all, in my net. She 

 had stored five caterpillars in one cell. All the caterpillars 

 were Loxostege sticticalis. 



At the base of the cliffs in Ness county, in which this great 

 colony of 0. papagonim was located, was a nairow alluvial 

 flood plain, which was matted with a variety of sedges and 

 grasses. In the midst of this tangle of vegetation 0. anniilatus 

 excavated a nest. 



My attention was first attracted to this nest on the afterr 

 noon of July 4, about five o'clock. The wasp had evidently not 

 been at work long, for the tube she was building was only 

 about one-third of an inch high. I watched her for nearly an 

 hour. During that time she made fifty-one trips into the bur- 

 row to remove earth. Ordinarily one of these trips was made 

 in thirty seconds, though occasionally more time was required ; 

 two required over a minute each. She also made ten trips for 

 water. She did not fly directly to the creek for water, 

 as did all the others of this species that I observed, but 

 went downstream to a sand bar. In most of these instances 

 she would return to the nest in forty seconds, but would not 

 always alight. She seemed greatly disturbed by my presence, 

 although I would always lie prostrate on the grass when she 

 went for water. Several times on her return from the creek 

 she would fly away again without alighting, and would return 

 several minutes later, hoping, no doubt, that I would be gone. 

 One time she was gone eight minutes. She was also bothered 

 by the wind, which had nearly stopped the activities of the 

 colony of O. papagorum earlier in the afternoon. She would 

 always alight on the grass above the entrance of her burrow, 

 and seemed to do so with considerable difficulty. Before alight- 

 ing she would always make a number of horizontal ellipses in 

 the air above her nesting site. Perhaps these flights above the 

 nesting site were to locate the exact position of the burrow. 



This wasp worked much as did 0. arvensis. She always 

 backed out of her burrow with the pellet of earth, and applied 

 it to the chimney with her mandibles and fore feet. Shortly 

 before I left she began dropping pellets in a pile about three 

 inches from the nest. 



The next afternoon I returned to watch this wasp. She 

 left the nest soon after I arrived, and returned in one hour 

 and twenty minutes with a caterpillar. She spent five 



