282 KANSAS UNIVERSITY SCIENCE BULLETIN. 



0. dorsalis, as I found her, was a burrowing wasp. I did 

 not know that she ever built cells above ground until I read 

 Mr. Hartman's paper. Usually she preferred to make her 

 home in an open spot in a lowland pasture, in a path or in a 

 well-traveled road. These nests were never found in sod, 

 although sometimes a few blades of grass might be found in 

 the space in which the nest was located. Even the vegetation 

 around the space was always short, except in one instance. 

 This exceptional nest I found in a stony knoll. The small 

 space in which the nest was located was surrounded by a tall 

 growth of mesquite grass (Bouteloua oligostachya) . The soil 

 in which the nests were excavated was always firm. The nest 

 was always a vertical or nearly vertical burrow, at the bottom 

 of which were one or two cells. No tube was built over the 

 entrance. This situation was the usual one. 



A variation from this form of burrow I found in the face 

 of a vertical earthen bank of the Saline river. I found there 

 a colony of eight nests, whose burrows led obliquely or hori- 

 zontally for one or two inches into the bank, and then down- 

 ward. The number of cells to each nest varied from three to 

 seven. 



The two types of excavated nests present a contrast to the 

 earthen cells of the Texan dorsalis, built under a tuft of grass, 

 which are described by Mr. Hartman. 



The nesting season of 0. dorsalis was at its height in the 

 month of August. A wasp carrying a caterpillar was brought 

 to me, July 24, by Mr. Williams. This was the earliest indica- 

 tion of nesting activities that came to my notice. In Osborne 

 county, on August 4 and 5, the excavating and storing of 

 seven nests were observed. At our next camp, in Rooks 

 county, from August 6 to 13, four nests came under my ob- 

 servation. In Graham county, from August 13 to 20, I counted 

 thirty-six nests either being built or stored. I might have 

 found many more, but they were so common I did not hunt for 

 them. In Norton county, from August 20 to 27, I believe they 

 were no less numerous, but I took no count. There was a 

 decided decrease in this line of activity in the next county, 

 Phillips, where we were from August 27 to September 2. I 

 found but two nests there. None was found after that. 



The dates including the period of nesting activities of 

 0. dorsalis may indicate the nesting period of only one gen- 

 eration. The colony located July 29, in the bank of the Saline 



