Scientific Name: Condylostylus patibulatus
Family: Dolichopodidae
Native Range: Eastern United States and Southern Canada, Pennsylvania*
Size: Really small
Active:
Color and Appearance: “Green body, black legs, black antennae, face with pale hairs, segments 2-4 of fore tarsi similar (female) or 2-3 short and 4 longer (male). Fore basitarsus of male with row of bristles on outside. In the Northeast, no other species has black legs and marked wings.”*
*From BugGuide.net (https://bugguide.net/node/view/478773)
August 16, 2020: Condylostylus patibulatus are really small. Really small. And fast. And skittish. BugGuide.net notes that they are among the more common flies in the Northeast and one of the first to be described in scientific literature. They are also common in our yard as tiny, brightly zooming specks. Photographs of them are inevitably blurry and frequently do not show the insect, because he or she has flown off before the shutter closed.
Condylostylus patibulatus on Sunflower Leaf 
Condylostylus patibulatus on Fragrant Sumac Leaf
