336 
Psyche 
[June 
some 20-30 females nested in a bare area measuring about 4x8m, 
which had been cleared of rocks and vegetation, possibly for pro- 
jected agriculture, in scrubby woodland in the foothills. The soil 
was a moderately friable, sandy loam. One additional nest was 
located in much harder and coarser soil in a schoolyard 0.5 km 
away. At Santa Maria, Catamarca, several nests were discovered 
in bare, firm, sandy loam in vacant lots in the city. At Las Termas 
de Rio Hondo, Santiago del Estero, six nests were found in coarse, 
hard-packed, sandy clay close to the banks of the Rio Dulce. 
The three sites in Argentina were all in areas of low rainfall, and 
were notably dry during the period of study. Collecting records 
suggest that Rubrica is active here only during the warm summer 
months (chiefly December-April) . In Trinidad, wasps were col- 
lected at almost all times of the year. Nesting activities, however, 
occurred mainly toward the end of the wet season and during the 
dry season, that is, December through May. 
Male Behavior 
In Argentina, males were frequently seen visiting various flowers, 
along with many females, but we observed no mating here. At 
Yacochuya, two males were seen consistently in the nesting area, and 
these males made several attempts to mate with females that were 
digging or opening or closing their nests. Much of the time these 
males flew about close above the ground and perched here and there 
with their wings partially extended. We saw no males at all in the 
large aggregation at Cali, Colombia. 
At St. Augustine, Trinidad, males were occasionally seen flying 
in the immediate vicinity of the nesting site. More usually they were 
seen resting and apparently sunning themselves on nearby vegetation. 
Similar observations were made by Vesey-Fitzgerald (1940), who 
also reported that males and females rest on vegetation at night, the 
two sexes separately, the males “in groups of many individuals to- 
gether.” Bodkin (1917) also reported large sleeping clusters, of 
unspecified sex, in Guyana. At Cali, Colombia, we searched sur- 
rounding vegetation carefully in the evening, but were unable to find 
such clusters. It was clear, however, that females do not spend the 
night in the nests and males do not dig “sleeping burrows,” as is 
the case in Bembix. 
Nest Construction 
Females dig effectively through the firm and often coarse substrate, 
