﻿42 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loo 



face, a few black hairs on the mesonotum, and generally blacker legs) , 

 but I can detect no differences in the genitalia. 



There is also a variety or subspecies occurring in the United States, 

 especially in the Rocky Mountain region, that is paler than the Alaska 

 material. Several other specimens are at hand that are slightly dif- 

 ferent, but I am inclined to think they are all variations of luniger. 

 The description given below is based on eight males and two females 

 from Matanuska, Alaska. 



Diagnosis. — Face with a median black line ; pile on the sides of the 

 thorax tinged with yellow; scutellum black haired; abdomen with 

 three pairs of isolated lunulate spots, their inner ends nearer the bases 

 of the segments than their outer ends. 



Male. — Face yellow with an abbreviated black stripe, which ends in 

 the depression, widens below and reaches the oral edge, and is gener- 

 ally connected with the shining black cheeks, decidedly receding be- 

 low the tubercle, the pile mostly yellow but often black down the sides 

 next to the eyes, face lightly pollinose on the sides; frontal triangle 

 yellow, heavily covered with yellow pollen except just above the an- 

 tennae where there are two arcuate narrowly connected black spots; 

 pile black; antennae black, yellow beneath the third segment, arista 

 thickened for two-thirds its length ; occipital pile whitish below, yel- 

 low above with several black cilia overhanging the eyes; ocellar tri- 

 angle black with black pile ; eyes bare. 



Thorax shining aeneous, pile pale yellowish, a few black hairs on the 

 sides just above the base of the wings. Scutellum opalescent yellow, 

 the pile black, with longer hairs and with some yellow hairs on the apex 

 and basal angles. Legs yellow, the basal one-half of the four front 

 femora and the basal one-half or more of the hind femora black, hind 

 tarsi with a median black ring, tarsi infuscated black above. Wings 

 hyaline, stigma brownish, halteres and squamae yellowish. 



Abdomen black with three pairs of isolated yellow spots ; first pair 

 triangular, inner ends pointed ; second pair arcuated, their inner ends 

 rounded and nearer the base of the segment than the outer ends ; third 

 pair similar but smaller and less arcuated ; apical margins of fourth 

 and fifth tergites and basal corners of fifth yellow. Venter yellow with 

 three large quadrate black spots, one each on sternites 2, 3, and 4 ; styles 

 of genitalia small, evenly contoured, yellow. 



Female. — Very similar ; facial pile usually yellowish but sometimes 

 black along the sides, front with a wide subinterrupted pollinose band, 

 legs less extensively black, tergal spots smaller. 



