2 
Psyche 
species. The pale markings are more constant than in 
many insects ; these, and the punctation, and the shape of 
the clypeal process in the female are of basic importance. 
In several of the species in this paper, Isolde , femur- 
rub rum, orestes, thione, the lower part of the outer edge 
of the lateral lobes is fitted to the edge of the eye for 
a short distance ; this occurs in some of the European 
species and is the normal condition in the subgenus 
Apiratrix. 
Some have used the number of spines on the hind tibia 
as of specific value, but in onr species it is not dependable. 
In a few species the males have the ends of the last ventral 
ridge developed, and provided with blunt teeth. In these 
species the lateral lobe does not reach the eye. 
The two subgenera may be distinguished by the follow- 
ing : 
At base of second ventral segment is a slightly raised 
area, often semicircular in outline; the stigma of the 
fore wings is brown to almost black Apiratrix. 
No raised area at base of second ventral segment ; stigma 
yellowish to ferruginous Cerceris. 
Subgenus Cerceris Latr. 
The majority of the species, and all of the larger ones 
belong to this subgenus. 
CERCERIS FEMALES 
1. No distinct clypeal process with a free apical edge, 
or not raised above general surface 2 
A distinct clypeal process, with free apical edge well 
raised above the general surface of clypeus 6 
2. No band on second segment of abdomen 3 
A yellow band on part or whole of second segment ... 4 
3. Face below antennae pale yellowish, except the nar- 
row black lower border of clypeus; snpraclypeal 
carina very long and high, bands on fourth and 
fifth segments quite broad orestes 
Face below antennae with much black; the hump on 
