NOTES ON THE EASTERN SPECIES OF CERCERIS. 
(HYM. PHILANTHID&.) 
By NATHAN BANKS. 
The species of Cerceris are among the prettiest of our ento- 
mophilous wasps; usually black, with bands and spots of yellow, 
of the general appearance of many species of Crabro. They 
are most abundant on flowers in July, some occur in June, and 
others as late as October. They are not especially shy, so are 
readily taken in the net. 
The sexes are easily distinguished as the male shows seven 
abdominal segments, while the female has apparently but six. 
In the male at each side of the clypeal margin is a series of hairs 
set close together, forming a hair-lobe. In the females of many 
species the upper part of the clypeus is elevated into various 
shapes, according to the species. In the female the pygidial 
area is rather dull, and slightly transversely wrinkled or rugose, 
with few hairs, while in the male this area is strongly punctate, 
and hairy. 
The characters of value for the distinction and identifica- 
tion of species are the coloration, the punctuation, the breadth 
of the face, shape of clypeal process in the female, of the clypeal 
margin and hair-lobes in the male, the length of the second 
joint of flagellum, and shape of the last joint, the distance of 
ocelli apart, the sculpture of the triangular area or enclosure at 
the base of the metanotum, the shape of the basal segment of 
abdomen, and the pygidial area at tip of body. Ina few forms 
there is a tooth or ridge on each side of mesosternum. The 
number and spacing of the spines on the hind tibie is variable, 
but sometimes useful. 
The color markings, as in other insects, are more or less 
variable; the spots on the metanotum are especially unstable, 
while the color of the hind femora is much more constant. All 
(except one) species have yellow spots or a band on the prono- 
tum, and with one exception there is a yellow band on the second 
abdominal segment; the face of the male is wholly yellow. The 
color of the stigma of wings is quite constant, and of consider- 
able systematic value. 
The sculpture of the enclosure on metanotum is of great 
value, but there is some variation observable when one examines 
a series of one species; however, a considerable difference in 
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