1980 ] Parker, Tepedino, & Vincent — Ammophila 
255 
Figures 1-4. Fig. 1. Silver removing prey from White’s nest after opening 
it. Fig. 2. White begins to replug the burrow after evicting Silver. Note that prey 
have not been returned to the nest. Fig. 3. Silver stings one of the prey which she 
has carried to a nearby fence post. Fig. 4. Silver returning the last of the prey to 
White’s nest. 
stung, and then carried into the thiefs burrow. Victimized females 
usually flew off after escaping their attackers. Because females were 
unmarked, it was not clear if the same wasps did all or most of the 
attacking or if the attackers ever foraged for prey in the field. 
Discussion 
Evans (1959) classified A. aberti as a delayed (rarely mass) 
provisioning species. Powell (1964) agreed but also suggested that 
progressive provisioning might occur. In contrast, our observations 
and nest excavations strongly suggest that A. aberti is primarily a 
mass provisioning species, at least in northern Utah. At the Cornish 
site, only two of 46 nests excavated immediately after completion 
contained larvae that were beyond the second instar while 30 nests 
contained eggs that had not yet hatched. In addition, observations at 
GF showed that wasps rapidly completed digging and provisioning 
their nests and did not reopen them after completion. 
Nevertheless, 14 nests (30.4%) did contain first or second instar 
larvae when excavated, and these nests do fit Evans (1966) definition 
