Banks, Greene, McAtee, and Shannon — Dist. of Col. Diptera. 197 



pleurae with yellowish brown pile, intermixed with black; posterior 

 margin of scutellum with rather long black bristles and short white pile. 

 Legs black, yellow on extreme apices of femora and bases and apices of 

 tibiae; tarsi black, the first two joints ventrally with a cushion of very 

 short golden pile ; lower margins of hind femora with very short, black 

 bristles which extend nearly the entire length. Abdomen shining bronzy 

 black and opaque; second segment opaque black except at anterior 

 angles, third segment opaque on posterior half, subshining in middle on 

 anterior half; pile short, black on opaque parts and brownish on the 

 shining parts. Wings smoky, stigma dark luteous. Squamae and hal- 

 teres darkened. Length: 6.5-8.5 mm. ; wing 5.5-7.5 mm. 



Female: Frons about two-thirds the width of one eye, slightly narrower 

 posteriorly, shining black, with short black pile posteriorly and longer 

 and denser white pile anteriorly, along eye an incomplete margin of 

 whitish pollen. First and second antennal joints black with very short 

 black pubescence basally. Face broader than in the male, more deeply 

 excavated beneath antennae. Mesonotum with very short white pile; 

 pleurae with the pile a little longer; whitish. A few rather short, black 

 bristles along side margins of mesonotum and posterior margin of scutel- 

 lum; Legs as in the male, except that the first tarsal joint of hind leg 

 is somewhat swollen. Abdomen shining black with a greyish reflection; 

 third and fourth segments each with an inwardly arcuate stripe of 

 whitish pile on their disks, behind these stripes the segments are a 

 deeper black, the third with an indication of a posterior opaque band; 

 pile along sides of abdomen whitish. Wings slightly smoky, sometimes 

 hyaline. Squamae white ; halteres yellowish white. Length: 6-7.5 mm. ; 

 wing 5.5-6.5 mm. 



Described from twenty-two specimens. 

 Type Cat. No. 20315 U. S. N. M. 



Male type; Cabin John, Maryland, October 30, 1915 (Shannon); allo- 

 type, female, Dead Run, Fairfax Co., Virginia, October 28, 1915 

 (Shannon); for other local records, see list of species, p. 180. All other 

 specimens recorded there and the following are paratypes: Riverton, 

 New Jersey, September 7 and 20, 1904 and 1908 (C. T. Greene); Manu- 

 muskin. New Jersey, October 8, 1901 (V. A. E. Daecke) ; Clementon, 

 New Jersey, October 4, 1904 (collector unknown). Usually taken on 

 Solidago. 



This species belongs to the group which is characterized by bare eyes, 

 short pubescence on the arista and marginal bristles on the scutellum. 

 The other females' of this group, pallipes, tristia, and leucoparea, are 

 further characterized by having a yellow spot on each side of the face 

 and the humeri and the scutellum partly yellow, but similis is black in 

 both sexes. C. similis male is less distinct, but may be distinguished 

 from pallipes male by its dark legs and shorter pubescence and from 

 tristis by having the pile on the dorsum of the thorax entirely black; 

 pile on abdomen rather short, the squamae darkened and the ciliae deep 

 blackish brown. C. tristis has the pubescence on arista and body rather 



