Length: most in the tribe are 5-9 mm
These midges are often attracted to lights; they may also found on flowers occasionally.
As is typical in this family, the males have very "furry" antennae. On this page, the top photo is of a female the bottom two are of males.
The most commonly encountered genus in the tribe Tanytarsini is Tanytarsus.
As the common name says, most Tanytarsini midges are green, but note that not all green midge-like flies are in Tanytarsus. See also, for example, the Ceratopogonid midge Stilobezzia viridis.
American Insects site