54 PROCEEDINGS OF THE NATIONAL MUSEUM vol.93 



Head with front of male at narrowest 0.20 to 0.23, usually 0.21, and 

 in female 0.24 to 0.27, mostly 0.24, of head width; frontal row of 

 seven to nine bristles in male and five to seven in female, extending 

 from apex of second antennal segment to two strong reclinate upper 

 frontals (preverticals) ; facial ridge bristly on lowest one-sixth; 

 gena less than one-fifteenth eye height; frontal orbit, face, cheek, 

 and posterior orbit light -gray-silvery pollinose; third segment of 

 antenna black, first and second segments varying from red to black 

 but usually red, third segment four and one-half times second in male 

 and four times in female; arista thickened on basal one-fourth, pe- 

 nultimate segment short ; palpus yellow. 



Thorax black usually gray-pollinose although quite often with a 

 tawny tinge ; five black mesonotal vittae, the median one obsolete be- 

 fore the suture; three or four postsutural dorsocentral macrochaetae, 

 usually four, sometimes three on one side and four on the other; 

 scutellum yellow covered with gray pollen, three pairs of marginal 

 scutellars and one smaller but strong decussate apical pair turned 

 backward, disk with one pair of discal scutellars; two sternopleural 

 macrochaetae; legs with tarsi black; tibiae, femora, and coxae yellow, 

 concolorous ; fore tibia with two median posterolateral bristles ; mid- 

 tibia with one median anterolateral bristle, inner ventral weak or 

 lacking, usually present, shorter than and situated on a level with or 

 nearer the tarsus than the lower of the two median posterolateral 

 bristles ; hind tibia evenly ciliate, with one longer bristle near middle ; 

 wing grayish hyaline, third vein with one or two bristles at base, 

 squama white. 



Abdomen covered with gray pollen, sometimes with a tawny tinge 

 except on dorsum of first segment and the very narrow (pencil line) 

 dorsal vitta ; although somewhat obscured by pollen, ground color of 

 venter and sides reddish yellow extending up onto dorsum some- 

 what on first, second, third, and sometimes basal portions of fourth 

 segment ; ground color of dorsum, usually entire fourth segment, and 

 ventral membrane black; first and second segments with a pair and 

 third with a marginal row of macrochaetae, fourth segment covered 

 with erect bristles about one-half size of macrochaetae on third ; usu- 

 ally without discals, but over 10 percent of specimens examined had 

 a nicely formed pair on third segment, and 2 specimens out of 90 

 had a pair of discals on second as well as on third segment; one 

 specimen lacked marginal pair of macrochaetae on second segment. 



Length 7 to 9 mm. 



Type locality. — Mount Washington, N. H. 



Distribution. — Maine 1, New Hampshire 1, New York 2, New Jer- 

 sey 5, Pennsylvania 1, Ontario 1. Published records not duplicated 

 above: Massachusetts (Townsencl, Johnson, Schaffner and Griswold), 



