The stable fly resembles the common housefly (Musca domestica), though smaller, and on closer examination has a slightly wider and spotted abdomen.[3] Adults are generally about 6–8 mm (1⁄4–5⁄16 inch) in length and a lighter color than the housefly. Unlike the housefly, where the mouth part is adapted for sponging, the stable fly mouth parts have biting structures.[4]