1979] Matthews, Hook & Krispyn — Behavior of Crabro 155 
4 
Figure 4. “Cliff” at the north beach site (site 3 in Fig. 1), containing numerous 
nests of Crabro argusinus scattered throughout the middle portions of the cliff. 
Females hunted prey along the high tide line among the washed-up debris (mostly 
Spartina reeds). 
Creek sites were scattered over a much larger area, with over 100 
nests estimated to be active in each area. In early October, 1978 we 
also excavated a few nests from a sandy road which led to the boiler 
site about 100 m away. Evidently we were too early for most of the 
fall nesting season, since, despite extensive searching, no C. argusi¬ 
nus were nesting at the other sites at this date and all nests found on 
the road were fresh and the population seemed to be greatly 
increased on the last day of our visit. 
Table 1 summarizes data obtained from 31 nest excavations of 
this species according to date and locality. At all sites burrows 
entered the soil obliquely at roughly a 60° angle to the surface and 
contained from 1-7 cells situated 3-5 cm from the sides of the tunnel 
end (Figs. 6-7). Prey accumulate in the bottom of the burrow and 
are later transferred to the cell. Eggs are attached to the throat of 
one of the largest flies situated venter up, head in-first, farthest into 
the cell. Burrow diameter was 4-5 mm and on level soil a distinct 
unleveled tunnel of soil accumulated around the entrance. The 16 
cells measured fell into 2 clusters, smaller cells 5X10 mm - 6X14 mm 
and larger cells 7X15 mm - 8X17 mm. 
