14 
Psyche 
[March 
Further studies will be needed to quantify these factors and to deter- 
mine if there is a real difference between temporary and final closure. 
The closure observed by Hicks (1935) in Colorado was presumably 
temporary, since no “tool using” was noted. The wasp studied by 
Hicks used “an old hackberry seed to close the upper end of the shaft. 
Sand was scraped in over this, and some score or more of objects were 
brought to further cover and conceal the nest site”. 
Provisioning the nest. — Females were observed on several oc- 
casions flying closely about low branches of willows and cottonwoods, 
apparently searching for prey. On one occasion a wasp seized a 
caterpillar on a willow branch, but the latter thrashed violently and 
the wasp left without stinging it; this was a considerably larger 
caterpillar than was ever found in the nests of the wasp. The 44 prey 
taken from various nests were all of roughly the same size (slender, 
12-18 mm in length) ; all were “naked” larvae, and all were green in 
color except for a few gray or reddish geometers. Specific identifi- 
cation of the prey was not possible, but many (perhaps all) belonged 
to groups which feed upon broadleafed trees rather than upon conifers. 
The following were recovered from the various nests dug out: 
Hymenoptera [det. B.D. Burks] 
Tenthredinidae : Neimatinae: Nematus (Pteronidia) 
sp. and Amauronematus sp. 28 
Lepidoptera [det. D.M. Weisman] 
Geometridae (four spp.) 7 
Gelechiidae (apparently all one sp.) 8 
Sphingidae: Smerinthus sp. (early instar) 1 
The use of sawfly larvae in considerable numbers is of interest, 
since Adriaanse (1947) found that A. pubescens restricts itself to 
caterpillars, the closely related A. campestris to sawflies. In the 
population of A. azteca studied, several nests contained nothing but 
sawfly larvae, a few nothing but moth larvae, and a very few (e.g., 
no. 2012) both sawfly and moth larvae. Individual wasps tended to 
stock successive nests wholly with sawfly larvae (rarely wholly with 
caterpillars), but there were numerous exceptions. I noted no shift 
in type of prey concordant with the progress of the season. 
Prey records from other parts of the range of this species indicate 
use of lepidopterous larvae of several different groups, including 
relatively hairy forms, but there are no further records of use of 
sawfly larvae. The single female studied at the Great Sand Dunes 
brought in a gelechiid larva very similar to those used in Jackson 
Hole. The nest studied at Yellowstone contained one noctuid, one 
geometer, and five larvae of lycaenid butterflies (Evans, 1963). 
