ISELY: EUMENID^ of KANSAS. 277 



Odynerus annidatus Say. 



I found no general rendezvous for the workers of this species. 

 This wasp is never found, unlike 0. arvensis and 0. papagorum, 

 coming and going in considerable numbers for water to a par- 

 ticular mud bar or cattle crossing in a stream. 0. annidatus is 

 not usually cautious about approaching running water. Many 

 times I have seen her alight fearlessly on a river roughened by 

 the wind, and ride over a riffle without mishap. She can take 

 water at almost any place along a stream. Why should she 

 need a special watering place? 



The males of this species, however, like the males of 0. 

 arvensis, do assemble for a dance in the sunshine. I noted 

 this but once. On the west side of a stone outcrop, about fifty 

 yards east of a small creek, was a long sand bank. Up and 

 down this sand bank played a number of male wasps of this 

 species. I collected six of them. This observation was made 

 August 15, in Graham county. 



This wasp was taken in all of the counties covered by the 

 survey in which eumenids were collected. It was less numer- 

 ous than 0. arvensis and 0. dorsalis. It appeared in greatest 

 numbers in Trego and Graham counties, both in the western 

 tier of counties covered. These counties, in the vicinity of our 

 camps, were more nearly treeless than any others visited. 



The variation of this wasp in nesting habits are as striking 

 as its variations in color pattern. Sometimes she is a digger 

 wasp, with a burrow and tube much like that of O. arvensis. 

 Messrs. Hungerford and Williams described her as a builder 

 of one-celled nests in open spaces in a prairie. I have found 

 but three nests. One had three cells ; it was dug through a sod, 

 in an alluvial flood plain of a stream. Another had twenty-two 

 cells ; it was dug in a barren, hard clay talus at the base of a 

 cliff". The third nest had been used previously by Pelopeus sp., 

 and was appropriated by a lazy or economical member of this 

 species. Because of the entirely different conditions connected 

 with each of these nests I shall deal with each separately. 



The wasp that used the old nest of Pelopeus I collected in 

 Trego county, July 12. About 100 yards from the Smoky Hill 

 river, near our camp, were chalk rock cliffs 110 feet high above 

 the flood plain. In cavities of these rocks and under ledges 

 were many nests of Pelopeus. While climbing among these 

 rocks I saw a eumenid, which proved to be 0. annidatus, carry- 



