1979] Matthews, Hook <& Krispyn — Behavior of Crabro 163 
maggot. Total development time for one of the Sphenometopa 
reared was 22 days. One cocoon excavated during April, 1978 was 
found to contain unidentified nematode worms. 
On sunny warm days females appeared to construct 2 cells per 
day. A period of intense provisioning activity occurred in the late 
mornings with a majority of nests closed from within during the 
middle part of the day. Late in the afternoon there would again be a 
period of intense provisioning activity. Observations of individual 
females revealed that flies were brought in at the rate of 1 fly every 3 
to 4 min during peak activity. A summary of all prey is given in 
Table 2, and includes over 50 species from 15 families. Brine flies 
(Ephydridae) and Dolichopodidae are the preferred prey, but in the 
late fall the anthomyiid Fucellia tergina constituted the primary 
prey at North Beach. Evans (1960) recorded 15 species of prey from 
his New York study which also were predominantly Dolichopodi¬ 
dae and Ephydridae. 
Males were seldom seen. Elowever, on October 7, 1978, 2 males 
were observed investigating freshly dug burrows at the road site 
adjacent to the boiler site. This date was clearly early in the fall 
nesting season, for no nests had been initiated at the boiler site 
nearby nor were any found at north beach, and during the subse¬ 
quent 2 days several new nests were initiated at this site. Another 
male was taken on November 4, 1976, dug from a “sleeping” burrow 
5 cm deep found among an aggregation of nests in a blowout area at 
north beach. On May 11, 1978 2 males were observed searching 
about nest entrances in a small sand pile at the mainland site. 
Males of about 3/ 4 of Nearctic Crabro possess an enlarged shield¬ 
like projection on the front tibia. Bohart (1976) suggested a clasping 
role for the male tibial shield, but pointed out that “this does not 
explain the great variety and ornamentation of the shield according 
to species” which may also serve a “display function” in courtship. 
In an attempt to learn the possible role of the male tibial shield, on 
28 May 1978 two reared males were placed in a plexiglass observa¬ 
tion cage (76 cm X 60 cm X 36 cm) with a reared female known to be 
unmated. One male repeatedly hovered 3-5 cm above the female as 
she crawled up the container sides and pounced on her several times. 
Males are not very discriminating; it was not unusual for one male 
to hover and pounce on the- other several times before searching 
elsewhere. Elowever, several mounting attempts were observed in 
which the male placed his shields over the eyes of the female, but the 
