Rocky Mountain bite flies

Symphoromyia (meaning bane/blight fly in Greek) is a genus of predatory snipe flies. Unusually for Rhagionids, some species of Symphoromyia are known to feed on mammal blood, including human blood. Symphoromyia species are stout bodied flies from 4.5 to 9 mm and with a black, grey or gold thorax, and the abdomen is coloured grey, black, or both black and yellow, black terminating with yellow, to completely yellow. The wings are hyaline or lightly infuscate.