Banks, Greene, McAtee, and Shannon — Dist. of Col. Diptera. 203 



pile. Abdomen shining black with a strong purplish reflection ; second 

 segment with an opaque spot in the middle; posterior margin of fourth 

 segment orange with golden pile. Wings lightly infuscated anteriorly; 

 anterior cross-vein joins discal cell a little beyond the middle. Length 

 about 12 mm.; wing about 10 mm. Two males: Waldoboro, Me. (J. H. 

 Lovell); Ottawa, Canada. 



B. FRONTosus Loew. 



Head in this species very distinctly triangular shaped, more so than 

 in the others. Eyes in the male barely touching. Antennae dark, 

 faintly reddish; arista yellow. Extreme tips of the femora and the 

 bases of the tibiae yellow. Hind tibiae in male armed with a tooth on 

 under side. Thorax dull aeneous, with whitish pile. Abdomen entirely 

 shining black. Wings somewhat infuscated, the transverse veins clouded. 

 Anterior cross-vein meets discal cell about its middle. Length about 13 

 mm., wing about 12 mm. Common throughout eastern United States. 



B. RiLEYi Williston. 



Eyes of male scarcely separated ; antennae blackish ; arista reddish- 

 brown. Dorsum of the thorax dull aeneous, with yellowish white and 

 black pile intermixed. Wings hyaline except for small clouds at base of 

 second vein, on anterior cross-vein and at angle of fifth vein; stigma 

 luteous. Anterior cross-vein but little beyond the middle of discal cell. 

 Abdomen with broad metallic bands on anterior margins of second, third, 

 and fourth segments. Length about 9 mm., wing 8 mm. Males and 

 females: North Carolina (Morrison); Cincinnati, Ohio; Dead Run, Fair- 

 fax Co., Va. ; common in a small Sphagnum swamp resting on logs (R. C. 

 Shannon). 



B. PARVUS Williston. 



Eyes distictly separated in male; antennae brownish; third joint much 

 smaller than in rileyi ; arista yellow. Frons and face brownish, with 

 silvery pile. Dorsum of thorax brassy, with rather long light pile. Abdo- 

 men bluish metallic with opaque cross bands on posterior margins of second 

 and third segments ; fourth somewhat yellowish on posterior margin. An- 

 terior cross-vein joins the discal cell distinctly beyond the middle. Length 

 8 mm. ; wing 6.5 mm. One male, the type — Colorado. 



Records of two rare species that have been obtained since the list was 

 sent to press are: Microdon megalogaster, Piney Branch, D. C, June 17, 

 1916, G. E. Quinter, and Eristalis flavipes, Beltsville, Md., on flowers of 

 Euthamia graminifolia, September 10, 1916, McAtee. 



