94 WASP STUDIES AFIELD 



cocoons. The cells varied in size from 2 to 6 mm., and 

 the cocoons fitted nicely into them. There was no fly debris 

 remaining; every evidence of the feeding proclivities of 

 the tenants was gone. 



Packard 1 says that they avail themselves of plants whose 

 stem has a pith which they can readily excavate, and 

 Cresson 2 found their nests in blackberry stems. The Peck- 

 hams found that this wasp uses the stems of plants ; in fact, 

 this is the famous insect that worked for forty-two con- 

 secutive hours with only a ten-minute intermission. They 

 found all tunnels of this species to be from thirty to 

 forty centimeters in length, and the completed cells con- 

 tained flies of four different species, all dead. Our notes 

 show that the species uses various species of flies. Perhaps 

 Packard was mistaken in stating that the females of stir- 

 picolus provision their nests with caterpillars, aphids, 

 spiders and other insects. 



Cresson 2 says that the Hymenopteron Diomorus hatched 

 from the nest of H. stirpicolus. 



Hypocrabro chrysarginus Lep. [S. A. Rohwer]. 



A log of wood was lying on the ground, and just beneath 

 it a heap of fine sawdust. This cone-shaped mound pointed 

 to a hole in the log directly above. Presently a black-and- 

 yellow H. chrysarginus flew into this hole and remained 

 therein until we lost patience. Among the sawdust on the 

 ground were four flies, apparently dead but quite fresh, 

 Sarcodexm sp. ?, Sarcodexia sternodontis Towns. [C. H. 

 T. Townsend] and Anthrax lateralis Say. [F. Knab]. 

 There was no way of determining whether the wasp had 

 dropped them as she entered the nest and had abandoned 



1 Guide to the Study of Insects, p. 158. 1889. 



2 Psyche 2: 189. 1878. 



