Muscidae

Slender to robust, usually strongly setulose flies, usually dull in color, black, gray, or yellowish, sometimes bright metallic blue or green, rarely with brightly colored hairs and resembling bumble bees; wings usually unmarked, sometimes with crossveins clouded, rarly with more extensive markings. Lenght 2-14 mm. (Huckett & Vockeroth 1987)