E. T. CRESSON, JR. 83 



following features: Frontal black spots broader, making the 

 median shining stripe narrower. Lunule polished, black and 

 more or less metallic tinged; facial tubercle black, very prominent, 

 not conical, but ridge-like, surrounded at base by a silvery line, 

 as are also the velvety facial spots. General color paler, es- 

 pecially of the face, legs excepting the til)iae and tarsi are yellow. 

 That this specimen represents a distinct species I will not 

 venture to consider, as it is not in very good condition. 



Tribe Sepedontini 



The genera of this tribe have only two scutellar bristles. In 

 other respects the face is long and apron-like; the second an- 

 tennal joint generally long and slender; the arista white plumose 

 or pubescent. Only one genus is represented within our fauna, 

 Init Thecomyia Perty of the Neotropical Region also belongs 

 here, and probably Cylindria Desvoidy of Europe will fall within 

 the tribe. 



SEPEDON Latreillc 



1804. Latreille, Nouv. Diet. Hist. Nat., xxiv, tab. metli., 196. 



1805. Latreille, Hist. Nat. Crust. Ins., xiv, 385. 



This genus was first diagnosed in 1804, for the reception of 

 Syrphus sphegus Fal:)ricius (1781), which species must be the 

 genotype. In our fauna the genus contains species of slender 

 flies with practically immaculate wings; the frons is deeply ex- 

 cavated and ridged; the ocellar bristles are microscopic or absent; 

 lunule prominent; face much produced below, rather snout-like, 

 with the shining, lower median portion, apron like. Scutellum 

 has only the two approximated apical bristles; the hind tibiae 

 without preapicals. The pleura and abdomen are without char- 

 acteristic bristles, and those of the mesonotum are weak or rudi- 

 mentary. 



Key to the Species 



1. Second antenna! joint robust, distinctly broader than first 2 



This joint slender, not broader than first 3 



2. Frons broadly excavated; frontal ridges well separated from each other 



and close to orbits fuscipennis 



Frons narrowly excavated with ridges prominent and well separated from 

 orbits. (Western) pacifica 



TRANS. AM. ENT. SOC, XLVI. 



