Jeff Hahn, University of Minnesota Extension
Description: 1/4 inch long. Dull gray, similar to house flies; 4 narrow black longitudinal stripes on thorax; abdomen with light orange spots or with a black and gray pattern.
Where/When: Found in and around homes during fall and spring, and occasionally during winter.
Significance: Face flies feed on secretions around the faces of cattle and horses. They do not harm people and are only a nuisance when they cluster on the outside of buildings or get inside. They do not reproduce inside buildings.