The adults are about 1/4 inch in length, and they look similar to a house fly. Their color is a dull gray.
Face flies are normally seen outdoors from spring to fall. When the temperature is around 60°F female face flies tend to cluster in large numbers around the face of cattle and horses. Adults can also be found around bushes, tall grass, weeds, and fence posts. In the winter, adults seek shelter in such places as attics, wall voids and basements.
Although the preferred food of choice is the mucus and the watery secretions around the eyes, nose and mouth of cattle and horses, they will also feed on blood, flower nectar, and dung fluid.
Females lay their eggs in cow droppings that are new and undisturbed. The eggs can number from 30 – 230, and hatch in 10 – 23 days. From egg to adult, the developmental time averages 17 days.