91 



width of either parafrontal; one reclinate and usually two proclinate orbital 

 bristles; only a few black bristly hairs on parafrontals outside frontal rows; 

 vibrissae inserted length of second antennal joint above front edge of oral 

 margin, separated by distance about equal to length of second antennal joint; 

 no scattered bristly hairs in region lateral to vibrissae; facial ridges bare except 

 for one or two small bristles above the vibrissae; antennae extending to length 

 of second antennal joint above the vibrissae, the second joint rufous, third 

 joint one and one-half to two times as long as second, yellow, usually overlain 

 more or less completely with blackish tomentum; arista thickened on basal 

 half, penultimate joint slightly longer than broad; sides of face bare; in profile, 

 bucca equals one-tenth eye-height, and is subequal to parafacial; proboscis 

 almost as long as height of head, labella fleshy, palpi yellow, slightly clavate. 

 Thorax cinereous, with five rather indistinct black vittae, the outer pair broad 

 and obscure; usually two postsutural dorsocentrals, sometimes a weak third 

 anteriorly, two strong sternopleurals, three marginal scutellar bristles of about 

 equal size. Abdomen densely gray pollinose over black, without reddish spots 

 on the sides, with row of three obscure black spots on apices of intermediate 

 segments; the second segment with a pair of weak median marginal bristles, 

 third and fourth with marginal rows of about eight. Genitalia as in vigilans; 

 sides of fifth sternite roundly angular at apex, not lobiform. Wings hyaline; 

 without costal spine; one bristle at base of third vein. Legs black; middle tibia 

 with one small bristle on outer front side near middle ; pulvilli of fore foot about 

 as long as last tarsal joint; hind femur without villosity on inner proximal 

 surface. 



Female. — -Front at narrowest 0.27 (average of five) of the head-width. Pul- 

 villi much shorter than last tarsal joint. Genitalia non-piercing, telescoped 

 within abdomen, in repose. Otherwise like the male. 



Length 4.5 to 6 mm. 



Type. — Male, in the U. S. National Museum, from Moss 

 Point, Mississippi. 



Allotype. — Female, in the U. S. National Museum, from 

 Moss Point, Mississippi. 



Described from the following material: one specimen from 

 Manomet, Massachusetts, July 17, 1904 (J. A. Cushman); seven 

 females, Chesapeake Beach, Maryland; two males, Sandusky, 

 Cedar Point, Ohio (J. S. Hine) ; two males and one female, 

 Lafayette, Indiana (J. M. Aldrich); seven males and eleven fe- 

 males, Moss Point, Mississippi, September 8, 1922 (H. W. Allen) ; 

 two males and three females, Mobile, Alabama, September 4, 1922 

 (H. W. Allen) ; seven males and six females, Gulfport, Mississippi, 

 September 10, 1922 (H. W. Allen); one male and one female, 

 cowpeas, Agricultural and Mechanial College, Mississippi, 

 August 31 to September 1, 1922 (H. W. Allen) ; one male, College 

 Station, Texas, September 9, 1920 (H. J. Reinhard) ; one female, 

 Owen's Lake, California, labeled "on flowers of Asclepias" (J. M. 

 Aldrich); one specimen in the U. S. National Museum labeled 

 "Parker, Note No. 25 ", concerning which Professor Parker states, 

 "This fly followed Oxybelus quadrinotatus Say into its burrow as 

 the latter entered carrying a house-fly. As the fly came out of 

 the burrow, it was captured, as was Oxybelus as she emerged soon 

 afterward." 



One male and three females from Moscow, Idaho (J. M. Aldrich, 

 in the U. S. National Museum, differ slightly from the typical in 



