160 PROCEEDINGS KXTOMOLOOICAL SOCIETY 



formation regarding the type of pilosula which has enabled me to 

 place it correctly in the key and also for confirmation of my opin- 

 ion as to its generic position. 



KEY TO SPECIES. 



1. Wings not entirely hyaline, either with a spot at apex of second vein 



or with a distinct infuscation. . 

 Wings entirely hyaline.. 



2. Wings with a small black spot at apex of second vein (Toronto, Can.) 



pseudostign/a Johnson 

 Wings with their greater portion infuscated. 3 



3. Thorax and scutellum black (111.)... . Jumipennis Malloch 

 Thorax mostly yellow and scutellum entirely so. . 



4. Third antennal joint black; mesonotum without a white spot behind 



humeri (N. H.) obscuripennis Johnson 



Antennae entirely yellow; mesonotum with a white spot behind humeri. 



,-/>/( in/idus, n. sp. 



5. Haltercs yellow 



Halteres with at least the knob black. 7 



6. Scutellum black (Pa. 111., N. H.).. . .dorsalis Loew 

 Scutellum yellow (N. H.) ephippium Zetterstedt 



7. Legs entire yellow (N. H., Vt.) . .montanus Coquillett 



Legs with distinct black marks 



8. Thorax ' ; black, Lower half of pleura; and scutellum yellow (111.). 



apicalis, n. sp. 

 Thorax and scutellum yellow, disc of mesonotum with black marks 



(Pa.) festivus Loew 



Thorax and scutellum glossy black (La.)... ..pilosula Becker 



Gaurax apicalis, n. sp. 



Female. Glossy black. Head orange-yellow; occiput and frontal 

 triangle glossy black, sides of frons posteriorly brownish; face whitish 

 yellow; antenmr yellow, third joint reddish above; clypeus blackish; 

 palpi and proboscis yellow. Thorax glossy black, lower half of pleura 

 and scutellum pale yellow. Dorsum of abdomen glossy black, venter ob- 

 scurely yellowish, subopaque. Legs whitish yellow, a streak of postero- 

 ventral surface of apical fourth of mid femora and the whole of the apical 

 fourth of posterior surface of hind femora black. Wings clear, veins 

 brown. Halteres yellow, knob black. Short hairs on body and legs pale, 

 bristles black. 



Frons slightly broader than the combined width of eyes, and, posteriorly, 

 broader than long, the sides convergent anteriorly; triangle extending 

 beyond middle of frons, equal-sided, the lateral margins slightly convex: 

 orbits with rather strong hairs; antennae of moderate size, third joint 

 disc-like; arista slightly longer than anterior width of frons, hairs sparse, 

 upright, not very long; cheeks almost indistinguishable. Disc of mesn- 



