1920] Melander — Sy7iopsis of the Dipterous Family Psilidce 93 



rior orbits blackish; frontal triangle attaining suture and occupy- 

 ing half of the front at the ocelli; face greatly receding, antennal 

 grooves white- velvety, center stripe wide and polished; eyes small, 

 nearly round, not reaching front margin of profile by one-fifth 

 their greatest diameter and the hind margin by about one-third, 

 facets uniform, cheeks deeper than eye, orbits distinctly sunken; 

 occiput flat, swollen in back of the cheeks, with fine yellow hairs; 

 palpi tipped with brown; antennae greatly lengthened, basal 

 joints small, third joint twenty times as long as the second, arista 

 yellow, the thickened basal part with brown tip, pubescence micro- 

 scopic. Thorax testaceous, notum centrally broadly black in front, 

 vestiture pale yellow, bristles weak and black, one dorsocentral 

 and one pair scutellars; metanotum centrally blackened; meso- 

 pleurse with white hairs below. Abdomen piceous, sides toward 

 the base yellowish; genitalia minute. Legs yellowish. Halteres 

 pale yellow. Wings nearly hyaline with a brownish tinge, veins 

 firm and brown, sections of fourth vein proportioned 2: 5: 4, 

 third and fourth veins apically parallel. 



Two specimens. Paradise Valley, Mount Rainier, Wash., 

 August, 1917. 



Pseudopsila Johnson. 



Thorax entirely black (N. H., Mass., N. Y., Can.)., .fallax Loew 

 Thorax yellow, marked with black 2 



2. Dorsum without lateral margins of black 3 



Dorsum with lateral margins of black 4 



3. Humeri and upper half of pleurae black (Vt., N. Y.) (Proc. 



Acad. Nat. Sci. Phil., 1919, 193) {Psila) . .angustata Cresson 



Anterior margin, pleurae, metanotum and a narrow dorsal line 



black. (Me., N. H.) (Psyche, 1920, 18) . . perpolita Johnson 



4. With broad lateral margins only, upper half of pleurae black. 



(Conn., Me., N. J., Pa., Quebec) (Psila). . .bivittata Loew 



With a broad anterior and lateral margins, upper half of pleurae 



black. (N. H., Mass., Conn., Va.) (Psila) . . .collaris Loew 



Psila Meigen. 



Mesonotum and pleurae entirely yellow 2 



Thorax more or less black; abdomen wholly black 5 



