PSYCHE 
Vol. 54 
March, 1947 
No. 1 
SYNOPSIS OF WEST COAST GERCERIS 1 
(HYMENOPTERA, CERCERIDJE) 
By Nathan Banks 
Holliston, Mass. 
The first species of Cerceris described from this area 
was C. calif ornica by Cresson in 1865. Since then Pro- 
vancher described one, Viereck one, Mickel five, and the 
author several. Having received some additional ma- 
terial, I have put all in synoptic form. Several species 
described by Viereck and Cockerell from New Mexico 
occur in southern Arizona, and in a few cases in southern 
California, so I have included such as I know to occur in 
southern Arizona. 
It has been impossible to be sure in every case to asso- 
ciate the sexes correctly ; in some instances either of two 
species might belong to one of the opposite sex from what 
is now known, therefore I have described such forms 
separately. 
In the males I find that the shape of the middle lobe of 
the clypeus and the breadth of the hair-lobes are very 
useful. The sculpture of the enclosure, though usually 
fairly constant in each species, is sometimes variable, so 
of less value than previously considered by writers. The 
sculpture of the pygidium is less variable, but often simi- 
lar in several species ; the general shape of the pygidium, 
and the crest of hair at sides quite constant, although 
often differing in the sexes. 
Length and density of hair are also of use. There is 
little to be found (so far) in the wing, the length of the 
pedicel of the second submarginal cell is different in a few 
1 Published by a grant from the Museum of Comparative Zoology at Har- 
vard College. 
1 
