120 HYMENOPTERA. 



ventral plate unlike that of any other species ; apical lobes not well 

 separated, merely broad, thin, extensions of the pedicel with a few 

 spine-like hairs apically, (fig. 45). 



Fetnale. — Distinguished by its comparatively large size, dark collar, 

 narrow lateral marks on face, heavily punctured head and thorax, and 

 impunctate abdomen with glossy first segment. Somewhat larger than 

 the male which it resembles in general structure. 



Sculpture. — Practically the same as that of the male, but more sparse 

 punctures on thorax. 



Yellow Makings. — Face marks limited to narrow stripe on each side 

 of face, usually not extending above antennal sockets, (fig. 130). 

 Spots on tubercles, and sometimes on tegulae, and spots at base of 

 tibiffi yellow. 



Habitat. — Apparently not restricted, but found in greater 

 numbers in the Rocky Mountain States. Probably 90 per 

 cent, of the specimens have been taken in Colo., N. M. and 

 surrounding States. It has been found, however, in the 

 eastern States and in Canada. Recorded on ScroplnUaria, 

 CratcBgus, Lappula, Cleojne, Lmum, Dasiphot^a, Pentstemon, 

 and Phacelia. 



Specimens examined: about forty, from Colo., N. M., and 

 Canada. 



This species is very well marked, and clearly differentiated 

 from all others : it has no near relatives, but probably most 

 resembles P. tridentulus Ckll. The eighth ventral plate is 

 entirely distinct, being of a different form than the others, 

 but is nearest to that of P. tridentulus, as is the armature. 

 So far as known there is little variation in this species, espe- 

 cially in the males, of which there are over thirty in the col- 

 lection at hand. The females closely resembles forms of P. 

 episcopalis Ckll., but the variation is in the latter species. I 

 think it highly probable that P. elliptica Kirby, (1837), is the 

 same as this, but until some authentic descriptions, or speci- 

 mens can be obtained the older name will have to be ignored. 



THE MODESTUS DIVISION. 



This division is characterized in the males by the short, 



simple, truncate, distal pedicel of the eighth ventral plate, 



lacking apical lobes and pubescence ; by the simple, hairy 



wings of the seventh ventral plate, without tooth-like projec- 



