1987] 
West-Eberhard — Xenorhynchium nitidulum 
321 
ing,” in which several prey are brought to the cell in quick succes- 
sion when the larva is nearly grown, and the cell is then sealed. 
The chrysidid wasp, Stilbum cyanurum, probably opens an ovi- 
position hole in the cell wall after the host cells are sealed (see 
Bequaert, 1918; Iwata, 1976, p. 57). The sticky covering of X. nitidu- 
lum nests may provide some protection against the attacks of such 
intruders. 
Even though brief, these observations show that Xenorynchium 
nitudulum should be classified as at least “primitively social,” 
defined as nest-sharing without a reproductive division of labor. Of 
the five females associated with the two inhabited nests of this study, 
all were mated, and all except a very young (probably recently 
emerged) individual had developed ovaries. Of the five females, 
three were known to be active caretakers of the nests; one was 
observed provisioning, one carrying mud, and one defending the 
nest by stinging an intruder. The combination of dissection and 
behavioral data indicates that the females associated with the nests 
were not simply resting there, but active residents of shared nests. 
A male which emerged in captivity attempted copulation on the 
nest with a female which emerged a day later. Each time the male’s 
gentalia were extruded he placed his mouthparts just behind the 
female’s head and bit at her mildly. When mounted the male period- 
ically fanned his wings and while doing so lowered his antennae 
against those of the female, as in Polistes and some other vespoid 
wasps (see West-Eberhard, 1969 and references therein). Intromis- 
sion was not observed. These two adult wasps fed on raisins and 
water, and survived for several days in the jar containing the nest. 
Although they wandered about the jar during the daytime, at night 
the female always sat inside one of the empty cells (not always the 
same one) facing out. The male was less consistent in his sleeping 
habits, sometimes sitting in a cell facing inward, once facing out- 
ward. He usually spent the night sitting on the surface of the nest 
rather than in a cell. 
Folklore 
Xenorhynchium nitidulum is a common wasp in Orissa and other 
parts of India (see Vecht, 1963). Because of its habit of building 
nests on human habitations, it is familiar to the residents of the 
region. Mrs. Rukmini Patnaik, whose family is from a village near 
