Most are black or dull brown, but some are yellowish in color. Very small—1/16- to 1/8-inch. The arched thorax of the adult gives them a humpbacked appearance.
Characteristically short and erratic flight. Adults have a peculiar habit of rapidly running across windows, TV screens, tables, walls and plant foliage. These flies are frequently mistaken for "gnats."
Some species feed on fungi, while others are parasites of various insects.
Larvae develop in moist areas where organic material and standing water are present. Phorid larvae also develop in animal matter. The entire life cycle lasts 25 days or more, depending on the environmental conditions and the availability of food.
Drains should be the initial inspection site when encountering an infestation. The adults are often seen flying in areas located away from the source of infestation.