460 
Psyche 
[Vol. 92 
in the morning, before satellite flies were active. Certain pompilids 
and sphecids are less afflicted than related species because they 
overwinter in the adult stage and nest during the first warm spring 
days when few or no cleptoparasites are present (O’Brien and Kur- 
czewski, 1982; Aim and Kurczewski, 1984). There was no daily or 
seasonal adjustment in provisioning times by A. harti related to 
peak fly activity. S. vigi/ans is a generalized cleptoparasite and many 
other fossorial wasp species were present at the study site. 
Diversionary provisioning flights may be a means of deterring 
trailing satellite and related flies (Evans, 1963, 1970; Alcock, 1975; 
Matthews et al., 1979; Evans, et al., 1980, McCorquodale, 1984). 
Female wasps may perform elaborate flight manuevers incapable of 
being followed by the flies, they may take a long time in reaching the 
nest which may result in the fly losing interest, or they may freeze in 
a populated area and the fly may become distracted by another 
wasp. The latter two behaviors were observed frequently in A. harti. 
A. harti may exhibit these behaviors more often when initially pro- 
visioning a nest or when provisioning a young larva than when 
provisioning an older larva, but our data are insufficient to support 
this. Wasp species exhibiting progressive provisioning may not have 
evolved elaborate diversionary flights or other such “pre-parasitic” 
behaviors because of the ability of their larvae to outcompete mag- 
gots introduced into the cells (“post-parasitic” behavior). 
Nest cleaning may be designed to rid the burrow of cleptopara- 
sites. It is possible that S. vigilans larviposits after it enters the 
burrow and the maggot may then crawl downward into the cell. 
However, it is more plausible that the fly is attempting to contact 
the prey as it is carried down the burrow, based upon the behavior 
observed above ground. Burrow cleaning may remove any maggots 
so deposited. Evans (1966) observed debris being removed from 
nests of several Bembix species and suggested that this behavior 
prevents maggots from maturing on the excess food remains not 
consumed by the larva or may even remove maggots already present 
in the debris. The sand removed via the burrow cleaning of A. harti 
needs to be examined for the presence of maggots, although pres- 
ence of maggots in the sand merely proves that S. vigilans will 
deposit maggots in the burrow and not that the function of burrow 
cleaning is to remove maggots. An alternative function of nest clean- 
ing may be to facilitate the transport of prey to the cell by removing 
