E. T. CRESSON, JR. 115 



are broad, usually as broad as the third antennal joint, but often 

 narrower; however, never linear and concentric with the orbits. 

 The frons are generally dark with lighter areas about the bristles 

 and the ocellar ti'iangle, conspicuous, sometimes in very dark 

 colored specimens these markings are, or nearly, obsolete; in 

 which cases the face is usually more leaden in color. 



The males have the ciliation of the fore femora normal. Of 

 course those species having the flattened area on the antennae 

 must not be confused with this. The following description is 

 full, this species being the genotype. 



Description. — Black; base of tarsi more or less ta^A^ly to yellow, sometimes 

 black; halteres white or yellowish; wings hyaline with cross veins and 

 apjiendages generalh' clouded; veins dark. 



Oparjue. Frons dark browii, more or less intricately varied with hghter 

 markings, or sometimes nearly black; the lighter markings, gray or yellowish, 

 are most distinct as orbital spots and subcircular areas sm-rounding the ocellar 

 tubercle and the shining black spots at the base of the bristles. -Face varying 

 from almost silvery to dark brown, generally with tliree yellow to brown 

 spots, one on the carina and the other two mesad of the upper bristles'; para- 

 facial spots distinct. Cheeks, clj-peus, lower orbits and post orbits gray. 

 Third joint of antennae in certain angles somewhat gray or yellowish. 



Mesonotum gray to ochreous with numerous dark brown irrorations which 

 sometimes coalesce forming large areas of such color; between the dorsocentral 

 rows there are generally, especially anteriorly two or three dark stripes. 

 Pleura and metanotum gray; mesoplem-a and scutellum irrorated with dark 

 brown, rarely immaculate. Sternopleura and pectus darker to nearly black. 

 Abdomen gray to yellowish, more or less irrorated; bases of thii'd to fifth seg-" 

 ments dark brown, more shining, which color attenuates laterally and medianly 

 with more or less distinct medial extenuation attaining the apical margins; form- 

 ing a pair of brown median stripes; second segment with the stripes seldom 

 complete and the brown basal areas usually isolated or limited to the lateral 

 angles. Legs sparingly dark brown pruinose. All bristles black with more 

 or less distinct shining black spot at their- bases. 



Head as broad as high or broader. Eyes round or slightly obli(iuc. Frons 

 nearly one and a half times as broad as long, about half as broad as head, 

 sparingly setulose anteriorly; orbits parallel. Face as broad or broader than 

 long, rarely narrower; facalia broad, setulose, with two or more medianly 

 curved bristles, the uppermost being strongest and at middle of profile. Cheeks 

 one- to two-thirds diameter of ej'es. Third antennal joint longer than broad, 

 subcorneal, long pilose above (fig. 4). Abdominal segments subequal; sixth 

 of male just visible, roundly truncated. Fore femora of male densely ciliate 

 on lateral flexor margin with normal bristles in series complete to apex; mesal 

 series weak. Wings with second costal section two and a half to three and a 

 half times as long as third; fourth vein generally emitting one or more stumps 



TRANS. AM. ENT. SOC, XLII. 



