They also feed on blood from the wounds that other flies make on cattle. Face flies do not bite and are not known to carry germs that cause human diseases. But they can transmit diseases to horses, donkeys, and cattle. The face fly looks like the common house fly, but they differ in their habits. Mature face fly larvae are yellowish instead of white, but otherwise resemble house fly maggots.
Face flies hibernate in barns, houses, and other shelters.
The first known face flies in North America were discovered in Nova Scotia in 1952. They probably came from Europe. The flies soon spread throughout most of the United States. The face fly is in the order Diptera. It belongs to the house fly family, Muscidae.