BEHAVIOR OF POMPILID WASPS 83 



beside it. When we intruded too near, she flew to the log 

 above, rested, made her toilet and visited the spider for a 

 few seconds. Then she went forth on another tour of in- 

 spection of the log walls clear to the very top and down 

 again, by a circuitous route, examining every crevice on the 

 way. Once more she rested a while and made her toilet, 

 then went to the original crevice and carried her booty into 

 a nearby cranny, which she had just passed with casual 

 notice, and dragged it far in out of sight and beyond our 

 reach. 



This wasp, then, seems to have a propensity for building 

 nests in the crevices of stone walls, and the propensity prob- 

 ably had its origin in the days when the loose stones of 

 bluffs or hillsides was the only place for the species' abode. 



Pseudagenia (Agenia) architecta Say [S. A. Rohwer]. 



Under the loose bark on a log, tangled in a mass of 

 spider-web, was a pretty little two-celled nest of mud. It 

 was treasured until P. architecta emerged from it, revealing 

 its authorship. 



Later in the season several similar cells were found at 

 Cliff Cave, near St. Louis, Missouri. They were always in 

 pairs (see fig. 16), neat, thin little cells joined end to end 

 like sausages. 



The Peckhams 11 found a similar dainty mud nest hidden 

 away in the folds of a flag when they unfurled it on July 4. 

 Each cell contained a dead spider and a wasp larva. They 

 spun their cocoons on the 7th, 8th and Qth of July, and on 

 July 29 a male emerged and on August 2 two female adults 

 appeared. 



Wickham 12 found one in Iowa dragging off a spider, a 



11 Bull. Wise. Geol. & Nat. Hist. Surv. Ser. I. 2: 165-166. 1898. 

 12 Ent News 9: 47. 1898. 



