1935] Larva and Puparium of Physocephala sagittaria 147 
As de Meijere (1903) has pointed out the number of 
wart-like protuberances on the stigmal plates varies much 
in the known larval forms. This writer figures the stigmal 
plates of the three genera known in the larval stage and 
there seem to be considerable differences there. The pres- 
ent writer is of the opinion that were known larval forms 
available it would be quite possible to make at least a gen- 
eric key. 
The only larval key known to the writer which includes 
this family is that of Brues and Melander (1932). These 
workers attempted only to separate the family from related 
families. They mentioned that the wart-like antennae were 
tipped with a sclerotized ocellus-like ring but the present 
writer could find no such structure on the species considered 
in this paper. The conopid genera, keyed out below, have 
been reared from the following genera of Hymenoptera: 
Zodion: from Hylaeus , Odynerus, and Halictus; Sicus from 
Bremus; Physocephala from Apis, Xylocopa, Bremus, Bem- 
bex, Philantus, Eucera, Halictus, Megachile, and Sphin- 
gonotus. These three conopid genera have been reported 
only from genera of bees and wasps. Of the ten North 
American genera of Conopidae, three are known as larva 
and the following key is offered to these: 
1. Two elongate, distally tapering structures projecting 
from the caudo-ventral region of the body. Tracheae 
extending into these structures Zodion. 
No such projecting structures present 2. 
2. Anterior spiracles present Sicus. 
Anterior spiracles absent Physocephala. 
Explanation of Plate 12 
All are enlarged figures of Physocephala sagittaria (Say) 
1. Dorsal aspect of puparium. 
2. Left lateral aspect of cephalo-pharyngeal skeleton of larva. 
3. Dorsal aspect of cephalo-pharyngeal skeleton of larva. 
4. Left lateral aspect of larva. 
5. ' Left posterior spiracle of puparium. 
6. Left posterior spiracle of larva. 
7. Cephalic aspect of head region of larva. 
8. Dorsal aspect of anterior region of larva with cephalo-pharyngeal 
skeleton showing through the cuticula. 
