THE EUMENIDAE 331 



eggs so that the one to emerge first is deposited in the up- 

 permost cell ; thus it can emerge first and leave the way 

 clear for the second inmate of the nest. We have as yet 

 no intimation as to whether or not such a condition may 

 hold in Odynerus. 



The season for O. dorsalis seems to be from about the 

 middle of July or the first of August to the middle of Sep- 

 tember, but stragglers are occasionally seen outside the 

 limits of those dates. The earliest individual seen was out 

 on July 2. 



Odynerus anormis Say [S. A. Rohwer]. 



On July 22, we carried home a hollow stem which bore 

 evidence of being occupied. Mud partitions divided the 

 pith-chamber in the stem into five cells. From these cells, 

 five Odynerus anormis emerged, from July 24 to 26. The 

 top of the cavity was not sealed, but was open for about 

 an inch; in this space we found Diptera puparia, which on 

 the next day gave forth adults of Sarcomacronychl trivit- 

 tata Townsend [C .H. T. Townsend]. We could not tell 

 whether these were there accidentally or whether the life 

 history of this fly is interlinked with that of O> anormis. 



At Lake View, Kansas, a little later in the season, we 

 saw two specimens of this wasp, and watched them for 

 over a half-hour, as they ran about constantly prying into 

 holes in the sand and often entering them. They showed 

 no discrimination regarding the size of the hole; some- 

 times the holes were those of very small bees, and some- 

 times quite large like BembLr burrows. We suspect that 

 they were foraging. 



The Peckhams 8 find this species making nests in stalks 

 and using caterpillars for provisions, although the species 



8 Wasps, Social and Solitary, p. 91. 1905. 



