1920] Melander: Nearctic Tetanoceridce 327 



6. Paramera of hypopygium in outline somewhat ham-shaped, terminating 



in a thin strip; third antennal joint more acutely triangular; general 



color ochraceous, thoracic vittic usually c^uitc indistinct 7 



Paramera short, the thickened portion hourglass-shaped, with explanate 

 and oblicjuely truncate end; interfrontal stripe usually not bordered 

 by brown; third antennal joint bluntly triangular; general color ferru- 

 ginous, thoracic vittas distinct; middle tibiae with preapical bristle. 

 Wash.,* Id.,* Cal.* obtusifibula, n. sp. 



7. Middle femora with preapical liristle on posterior side, hind femora with 



4 extensor bristles; paramera apically narrow and angulate. Mass.,* 

 N. H., Vt., Ct., N. Y., Pa.,* N. J., Md., Va., Can.. Mich. (Hough), 

 Wis.,* 111.,* Mo., Col. (Hough), N. Mex., Wvo.,* Mont.,* Ut., Nev., 

 Wash.,* Or. (Cole). Cal.,* B. C.,* Alaska*, Mex. {plumosa 

 Loew) vicina Maccjuart 



Middle femora lacking preapical bristle, hind femora with 3 extensor 

 bristles; paramera apically broad and ribbon-like. Mont.,* Id.,* 

 Wash.* soror, n. sp. 



8. Right underside of last hypopygial segment bearing a strong thumb-like 



process, basal portion of terminal paramera elongate and parallel- 

 sided, fifth tergite o^ subquadrate, the fourth sternite with two apical 

 dense patches of black spinules; third antennal joint ovoid, the arista 

 loosely plumose; interfrontal stripe narrow, stopping at opaque border 

 of frontal suture, and not bordered with brown, no antennal or cervical 

 dark spots; posterior ocelli approximate; costal border not dark. 



Mont.,* Wyom.,* Wash.* papillifera, n. sp. 



Hypopygium symmetrically globose, fifth tergite c? laterally rounded, 

 the fourth sternite with less evident patches of setulse; interfrontal 

 stripe encroaching on opaque frontal margin 9 



9. Upper side of third antennal joint distinctly excised, arista moderately 



plumose; usually a trace of the antennal-orbital spot, cervical spot 

 with brown center; ocelli usually equidistant; hind femora 9 usually 

 with 3 bristles above and 3 in lower anterior row; costal margin scarcely 



clouded 10 



Third antennal joint ovoid, but slightly flattened above; posterior ocelli 

 usually approximate; no posterior preapical bristle on middle femora, 

 hind femora of known females with 1 or 2 bristles beneath on anterior 

 edge 11 



10. Paramera short, broad and thin, irregularly rhomboidal, the apical 



portion semicircular; a strong preapical bristle on posterior side of 

 middle femora; posterior crossvein arcuate. N. H., Ont.,* Queb.,* 

 N. Y., 111.,* Wise.,* Col., Wyo.,* Mont.,* Wash.,* B. C, Alaska.* 



triangularis Loew 



Paramera long and slender, densely setulose along lower edge; middle 

 femora lacking the preapical bristle; posterior crossvein nearlv straight. 

 Eur.*; Ont., N. Y. (Fallen, Dipt. Suec, Sciom. 9 (1820); Cresson. G4). 



ferruginea Fallen 



1 1 . End portion of hypopygial paramera spirally hooked, much longer than 



basal portion; antennal and cervical spots distinct; plumosity of arista 

 rather short and close; thorax vittate; costa clouded, posterior cross- 

 vein straight and nearly perpendicular; 6 mm. Mont.*. . .spirifera, n. sp. 

 End portion of the contorted poUinose paramera expanded leaf-like 

 and transparent; no orbital or cervical dark spots; front semitrans- 

 lucent, the stripes not strongly differentiated; hairs of arista long and 

 sparse; thorax not vittate; costa and apical veins somewhat clouded; 



5 to 6.5 mm 12 



Paramera narrowly triangular, the end and basal portions more or less 



merging; arista openly plumose, the hairs long; 6 to 8 mm 13 



