156 
Psyche 
[June-September 
Considering the 2 main study localities (north beach and boiler 
site), comparisons of the different populations from the same season 
as well as comparisons of populations from different seasons at the 
same site reveal some rather striking differences (Table 1). Fall 
populations at the north beach site constructed nests with cell 
depths averaging 16.1 to 17.0 cm (2 successive seasons). Cells con¬ 
tained an average of 11.2 to 14.6 prey (2 successive seasons). Spring 
populations nesting at the same site constructed significantly deeper 
burrows, with cell depths averaging 28.9 cm and provisioned with a 
much larger number of flies (x = 30.9/cell). 
Comparing populations of the two main localities at the same 
season (spring 1978) also revealed important differences. Spring 
nests at the boiler site were significantly shallower and cells were 
provisioned with fewer flies per cell (Table 1). Prey preferences also 
differed somewhat, possibly reflecting differences in hunting habi¬ 
tats. The north beach population lacked ready access to salt marsh 
and appeared to hunt mainly along the beach. Even so, 12 of 32 prey 
species were represented in cells at both sites (Table 2). Ephydridae 
and Dolichopodidae were preferred prey at both sites. 
© 
Figure 5. Boiler site (site 5 in Fig. 1); Crabro argusinus nested in the flat area in 
the foreground. Back Creek runs adjacent to this site on the left, and an extensive 
area of salt marsh extends behind the viewer. High tides occasionally barely covered 
the nest area. 
