E. T. CRESSON, JR. 103 



femora (fig. 3) and the iiimsually long mesoplcural bristles at once 

 decide its membership in the Notiphilae. Further notes on the 

 position of this genus will be discussed in the systematical sum- 

 mary which I intend to give at the end of this series of papers. 

 The primary characters of the genus are the presence of three 

 extensor bristles on the middle tibiae (fig. 3) and the continuation 

 of the costa to the fourth vein (fig. 1). 



Generic Description. — ^Robust, mostly large species. Head generally broader 

 than high, higher than long. Eyes bare generally rounded. Frons broad, 

 with parallel orbits: vertex rounded; ocelli situated slightly in advance of the 

 vertical angle, with a pair of post-ocellar bristles diverging; the usual ocellars 

 well separated, parallel, situated in advance of, or opposite the anterior ocellus; 

 inner- and outer verticals strong, also distinct occipito-centrals present; a 

 strong reclinate frontal and two or three procHnate orbitals of which the an- 

 terior one is the strongest. Anterior portion of frons more or less setulose or 

 hairy. Face broad, bare medianly; foveae shallow; facaUa scarcely differ- 

 entiated, setulose, with a series of one or more incurved bristles along inner 

 margin, the uppermost of which is the largest; parafacial groove sharp and well 

 defined to oral margin. Cheeks generally broad with distinct bristles; lower 

 occiput moderately swollen. Clypeus always visible, moderately broad. 

 Palpi cylindrical. Antennae short; second joint subglobular, without distinct 

 apical "thorn"; third joint hardly twice as long as broad; arista long with long 

 hairs above. 



Thorax quadrate, dorsum convex, wholly setulose; no acrostichals; one 

 pair of prescuteUars; one anterior and two posterior dorsocentrals; one humeral 

 (long); one presutural; one supra- and one post-alar; two noto- and two or 

 more meso-pleurals, one of the latter being very long; one sterno-pleural. 

 Scutellum flat, roundly truncate apically with four long marginal bristles. 

 Abdomen broad as thorax, with five to six segments; fifth of male convex, 

 truncate; genital segments inconspicuous. Legs slender; fore femora of male 

 sometimes characteristically cihate beneath; middle tibiae of both sexes with 

 three erect extensor bristles, one at each extremity and one before middle. 

 Wings elongate, slightly overreaching abdomen; costa broken just beyond 

 humeral c. v., slightly notched at first, and extends to tip of wing at fourth 

 vein; second, third and fourth veins generally straight. Allulae narrow. 



Genotype. — The name for this genus was used for the first time 

 in 1862, in two separate publications, given in the above bibliog- 

 raph}' under the genus, without direct reference to each other, 

 so that one, unless knowing dates of issue of the two, is at a loss 

 to determine which reference has priority. It will depend upon 

 the actual dates of issue of these publications as to which of 

 three species can be used as the genotype. Osten Sacken in a 

 foot note in his Catalogue of the North American Diptera, 1878, 



TRANS. AM. ENT. SOC, XLII. 



