1980] 
Hook & Matthews — Biology of Oxebelus 
23 
had 1 cell and 0.9% had 6 cells). Final closure is similar to that 
reported for other Oxybelus (Peckham et al., 1973) and this process 
took 35.5 min (15 to 45, n=15). Ten nests made by one female had 
from 1 to 6 cells per nest. Females often constructed series of nests in 
localized areas (ave. distance between 9 nests by 1 marked female was 
10.9 cm, range 1.5 to 26 cm). One female was found nesting 400 m 
across salt marsh from its original nesting area. Intraspecific nest 
usurpation was observed once. 
Provisioning and Prey Carriage. The mean duration between 
provisioning trips was 7.2 min. (1 to 140, n=163) with interruptions 
for mating included. Provisioning was most frequent between 1000 to 
1700. Once a cell was full the female plugged the entrance from within 
the nest for oviposition and prey arrangement. Wasps provisioned up 
to three cells per day. 
Ninety-six percent of the prey from 149 completed cells consisted 
of three species of Diptera (Table 1). Cells averaged 7 flies per cell (3 
to 14, n= 152); prey arrangement and egg placement may be classified 
as Crabro-style (Iwata, 1942). 
Oxybelus sericeus females transported prey from salt marsh to the 
nest area using pedal type 1 carriage (Evans, 1962), using their legs to 
grasp the prey. Once alighted near the nest (5-100+ cm from the nest, 
termed the “initial landing site” in Peckham etal., 1973)afemaletook 
a few seconds to face in the general nest direction. At this point she 
either impaled the prey on the sting (Fig. 1) or continued to carry the 
prey pedally as she crawled and/or flew the remaining distance to the 
nest. Some females only used pedal carriage as they transported prey 
entirely in flight, omitted the initial landing site and dropped into the 
open entrance (only very small flies were carried in this manner, see 
below). 
Most Oxybelus transport prey from the point of capture to the nest 
area using pedal carriage (i.e. bipunctatus and uniglumis, Peckham 
and Hook, in press). Prey is then impaled and the nest entered. 
Oxybelus sericeus differs from the others in that females may enter 
the nest using either pedal or impalement carriage. Our observations 
suggest that prey size influences the type of prey carriage used. Large, 
bulky prey normally elicited impalement carriage while small, less 
cumbersome prey were carried pedally. Prey weight corroborates this 
(Table 1). Ephydrids and some otitids averaged the least in weight 
and were rarely observed impaled, while dolichopodids averaged the 
heaviest and were usually impaled. Impalement carriage allows large 
