182 DIPTERA OF NORTH AMERICA. [PART IV. 



Rostrum yellow, palpi brown; antennas black; those of the 

 male have moderately long verticils ; thorax sulphur yellow ; 

 mesonotum grayish-brown; pleurae without any brown stripes, 

 uniformly yellow ; halteres very slightly infuscated ; feet pale 

 tawny. Wings (Tab. II, fig. 4) comparatively longer than in 

 the preceding species ; the discal cell is closed in normal speci- 

 mens ; the tip of the auxiliary vein is a little posterior to the 

 origin of the prasfurca ; the interval between the tip of the first 

 longitudinal vein and the anterior branch of the second vein is 

 five or six times shorter than the interval between the tips of the 

 two branches of the second vein ; the inner end of the second sub- 

 marginal cell is pointed, very little anterior to the inner end of 

 the first posterior cell ; the third vein is straight and very little 

 convergent with the anterior branch of the fourth ; the inner end 

 of the marginal cell (angle of the praafurca) almost acute ; the 

 inner ends of the first and fourth posterior, and of the discal cell, 

 nearly in one line. Abdomen brown above ; margins of the seg- 

 ments yellow ; venter and forceps of the male yellow ; the latter 

 with linear, hairy, slightly dusky appendages. 



Hab. Trenton .Falls, N. Y. ; Washington, D. C. Among twelve 

 specimens, the discal cell is open in one only. 



4. O. "Iblaiida, 0. S. % and 9 • — Alae stigmate et marginis anterioris 

 parte apicaii fuscis ; verrulis transversis infuscatis ; venae iongitudinalis 

 secundse rami anterioris apex cum apice vense Iongitudinalis prinise 

 coincidens. 



Wings with the stigma and the apical portion of the anterior margin in- 

 fuscated ; cross-veins clouded ; the tip of the anterior branch of the 

 second vein is coincident with the tip of the first longitudinal vein. 

 Long. corp. 0.25—0.28. 



Syn. Gonomyia blanda 0. Sacken, Proc. Ac. Nat. Sc. Phil. 1859, p. 231. 



Rostrum gray, margined with yellow above ; front and vertex 

 gray, margined with yellow along the eyes ; antennae brown ; two 

 basal joints yellow. Thorax gray above, with two approximated 

 brownish stripes in the middle ; two hardly distinct lateral stripes ; 

 scutellum brownish, gray in the middle ; metathorax brownish ; 

 pleurae pale yellow, slightly hoary; halteres dusky, with dark 

 knobs ; feet pale yellow, pubescent ; tips of the femora, of the 

 tibiae, and the whole of the tarsi dark brown ; abdomen grayish- 

 brown ; lateral and posterior margins of the segments yellow ; 



