isely: eumenid^ of Kansas. 273 



Observations on nesting- habits were made at intervals 

 throughout the summer. Nests were noted in Rush and Ness 

 counties; from July 16 to July 30 nests were found. None 

 were found in the next three counties, but in the last three 

 visited — Norton, Phillips, and Smith — from August 20 to Sep- 

 tember 6, nests were again located. Females were as num- 

 erous at a pool near Smith Center, September 3, as they had 

 been at any place visited previously, indicating that the nesting 

 season was still in full progress at that time. 



The general direction of the digging of 0. arv-ensis, whether 

 she is working in level ground or in talus, is downward, and 

 not horizontal like 0. papagorum. At the bottom of her more 

 or less vertical burrow are the larval cells. Over the entrance 

 of the burrow is built a thick upright earthen tube. 



Of all the nests that I observed, in only eight had the burrow 

 been excavated as far as the brood cell when I opened it. Of 

 these only two were entirely finished before I interrupted the 

 process. These burrows ranged from three and one-half to 

 seven inches deep. The average was five and one-fourth 

 inches. The average diameter of the burrow was one-fourth 

 of an inch. This long burrow was never absolutely straight. 



The number of larval cells to a nest varies greatly. In six 

 instances I found only one cell to the nest ; in another instance 

 I found three cells ; in still another instance I found six cells. 



Of those nests in which I found but one cell, only one burrow 

 had been sealed by the wasp. Most of the others were still 

 being stored with caterpillars, and might have had other cells 

 added later. In two of these nests the cell was directly at the 

 bottom of the burrow; in the other four the burrow made a 

 sharp turn before entering the larval cell. All of these nests. 

 were situated in soil comparatively easy to dig in. 



The nest with six cells was excavated in the hard clay talus 

 at the base of cliifs along the Saline river. The cells were 

 arranged in three galleries, two in each gallery, one cell being 

 directly above the other. When I opened the nest five cells 

 were closed and one was empty, serving as a hiding place for 

 the mother wasp. The other nest consisted of three cells ar- 

 ranged one above the other. It too was in the clay talus. It 

 was located by Mr. Mallory. 



All but two of the cells in these nests were shaped like short 

 cylinders with somewhat rounded ends. The diameter of these 

 cells averaged one-half inch, and the length ranged from nine- 



