322 A. L. MELANDER. 



of the head. Thorax with four fuscous vittse. Hypopygium of the male small, 

 rather sunked and closed, the upper lamellse small, grayish black, the lower 

 small, testaceous, the central filament hidden. Coxse blackish, cinereous. Legs 

 red, with sparse black pile, the hairs of the tibiae and of the tarsi longer and a 

 little more dense; the extreme tip of the femora spotted with a black dot; apex 

 of the tibise blackish ; tarsi black, the base of the first joint often dark red ; pos- 

 terior knees of the male drawn out into three strong apophyses, one at the tip of 

 the femora and two at the base of the tibise. Halteres dusky yellow. Wings 

 rather long, the veins strong, fuscous, stigma pale yellowish, rather faint. 5 mm. 



Sitka, Alaska (Sahlberg). 



Unfortunately the few minor characters on)itted in this descrip- 

 tion make it impossible to include this species in our table. 



Mr. Coquillett determines specimens received from Prof. Cocker- 

 ell, from tlie Hudsonian Zone of New Mexico as Loew's species. 



The following characters are common to the remaining species, 

 which, with the five preceding, constitute a very natural group. 



Body black, closely pollinose, occiput biseriately black bristly, 

 densely above and beneath. Eyes dark red, separated as widely as 

 the posterior ocelli at the narrowest part of the front in the male, 

 and slightly more in the female. Palpi small, slender, curved, yel- 

 lowish, more or less fuscous at the base, with one preapical minute 

 black bristle, or none. Proboscis one and one- half to two times 

 the head-height, dark red, not thick but strong, the labella slender, 

 black. Antennae black, equalling the eye-height, the first two joints 

 cylindrical, with a few short black hairs, and more or less pruinose, 

 together shorter than the third joint; third joint lanceolate, opaque 

 jet black, the style one-third the length of the third joint, of smaller 

 diameter than the tip of the joint. Thorax quadrivittate, generally 

 with broad brown vittse, the middle ones abbreviated posteriorly and 

 the lateral ones anteriorly; the intervittal bristles minute, a small 

 median row present; a bunch of bristles under the halteres, dorsum 

 margined by three or four short macrochtetse. Abdomen straight, 

 opaque pollinose, longer than the head and thorax together, with 

 very few bristles and no pubescence; hypopygium small, closed, 

 densely pubescent, the central filament swollen at the base, of the 

 shape of a scorpion-sting, reddish. Coxse dusted, provided with 

 black bristles on the forward side, the hind ones always with a 

 bunch near the tip below, trochanters tipped with black or wholly 

 black, femora with a narrow terminal black ring if light colored ; 



