22 
Psyche 
[Vol. 87 
September. In 1978 the Boiler site (see Fig. 5 in Matthews et al., 1979) 
was mainly used. Observations were made from 0800 to 1800 on most 
days. Notes were taken in the field, supplemented with motion 
pictures of mating. Cell contents from nest excavations were 
transferred to sand-filled tins for rearing at room temperatures. Male 
observations used distinctively marked individuals and were mostly 
carried out at the Boiler site. 
Results 
Activity Periods and Development. Oxybelus sericeus is a multi 
voltine species that first emerged in May and continued to nest into 
October. Rearing data revealed that both sexes required about 26 
days (25 to 27 males, n=7; 26 to 27 females, n=5) to develop from 
hatched egg to an emerged adult. Males appeared first in the morning 
(0830 to 0930) about 15 to 30 minutes before females. After females 
ceased provisioning males dug sleeping burrows between 1700 to 
1900, 2 to 3 cm deep in the nest area. 
Nest Construction and Architecture. Nests were typically dug in 
exposed sand, but some females constructed nests under washed-up 
Spartina or shells. Nest structure is essentially the same as that of O. 
subulatus Robertson (Peckham et al., 1973). The only difference was 
the absence of a tumulus about O. subulatus nests because of its 
carrier-type digging behavior. Nest digging in O. sericeus was 
initiated by biting the surface and pushing back the loosened sand 
with the legs. As the burrow deepened sand was apparently gathered 
between the venter and hind legs and pushed up the vertical burrow, 
forming a tumulus. Tumuli were leveled after digging was completed 
and ranged 2 to 5 cm in diameter. Leveling consisted of females 
repeatedly raking sand 1 to 3 cm away in all directions from the 
perimeter of the entrance, and returning to the entrance. In 
multicellular nests filler sand for the completed cell was obtained 
from the nest side burrow and cell excavation. Excess sand was 
brought to the surface, forming a tumulus which was subsequently 
leveled. After leveling, females began “orientation” flights, meandering 
paths 1 to 5 cm above the nest area, which lasted 2 to 5 min. and 
covered lm 2 surrounding the nest. 
Cell depths averaged 7.9 cm (3.5 to 15, n=182). Cell dimensions 
varied, averaging 16.8 mm (8 to 24, n=97) long and 5.6 mm (4 to 7, 
n=99) wide. An average of 1.7 cells was present per nest (range, 55% 
