They are cylindrical and taper anteriorly. Each is outlined by a thin, dark band, with 3 sinuous-shaped slits surrounding a button located towards the inner edge. Puparia are whitish to greyish in colour and 5 - 7 mm long. The respiratory horns found along the posterior border of the 4th segment are small but visible, and are darkened basally. They only enter buildings during the fall to look for overwintering sites.
Female flies feed on secretions from the wounds and orifices of cattle and horses.
They may create superficial lesions with sharp prestomal teeth on their mouthparts in attempts to feed on blood. Larvae complete development and pass through 3 instars within approximately 1 week. Mature larvae move into the surrounding soil to pupariate and emerge as adults 1 to 2 weeks later. Face flies overwinter as adults in large clusters in barns and other buildings. Presence of face flies around the eyes and muzzle causes distress in cattle and horses.