THE SAWFLLES OF BOULDER COUNTY, COLORADO 99 



Subfamily DOLERINAE 



Prepectus wanting; proepisternum very large ventrally and meeting in the middle; 

 presternum triangular; metapostnotum large; mandibles long and strongly falcate; 

 third pleural suture strongly curved; the dorsal part of the metaepisternum very narrow; 

 mesoepimeron with an oblique carina dorsally; basal vein joining the costa much basad 

 of the origin of the cubitus; anal cell of the fore wings contracted basally and with an 

 oblique cross-vein. In nearly every specimen the second transverse cubitus is wanting; 

 in which case this subfamily may be easily recognized by its venation, as it is the only 

 group which has the transverse radius present, and the second transverse cubitus wanting. 



The larvae of Dolerinae live on grasses and sedges. 1 Very little is known about the 

 habits of the American species and, in fact, nothing is known of the western larvae. The 

 subfamily is of northern distribution and probably a number of species will be found in 

 the county. The adults appear in the early spring and are closely related and are often 

 difficult to separate into species, while the larvae may offer striking differences. 



Genus DOLERUS Panzer 



Eyes oval or rounded, strongly convex; malar space as long as or longer than the 

 pedicellum; head and thorax coarsely sculptured. 



(12) D. aprilis Norton. Black; abdomen, except two apical segments, rufo- 

 ferruginous; wings hyaline, slightly dusky; venation black; scutellar appendage finely, 

 longitudinally striate. 



Boulder, Colorado (S. A. Johnson). 



(13) D. simulans Rohwer. Black; pronotum, prescutum, scutum, and abdomen, 

 except apex, reddish-yellow or red; wings dusky hyaline; venation black; scutellar 

 appendage finely, longitudinally striate. 



Boulder, Colorado, May, 1907 (S. A. Rohwer). Collected at the mouth of Boulder 

 Canyon, on willow flowers. 



Subfamily TENTHREDININAE 



Prepectus wanting; proepisternum very large ventrally and meeting in the middle; 

 presternum usually triangular in outline; third pleural suture straight; mesoepimeron 

 without an oblique carina dorsally; mandibles long, strongly falcate; basal vein joining 

 the costa remote from the cubitus; transverse radius present; anal cell of the fore wings 

 not contracted basally, either meeting in the middle, or with a short straight cross-vein; 

 all of the transverse cubiti normally present. 



Here again the larvae are nearly unknown, and as far as the species of the Rocky 

 Mountains are concerned, they are entirely so. The food-plants of these insects are 

 usually herbs or shrubs, but as far as known there is no definite correlation between the 

 host-plant and these parasites. This subfamily is of northern distribution, and many 

 more species may be found in the Canadian and Hudsonian zones of the county. 



From the standpoint of North America this subfamily offers some interesting points in 

 geographical distribution. Macrophya is the dominating genus in the east, while Tenthre- 



1 The species of Dolerus recorded from Prunus by Clarke is not a Volerus, in fact it belongs to a different 

 ubfamily. 



