The adult Blue Blow Flies have a dull-colored thorax and a shiny metallic blue-green abdomen. They are about 5/16” long. The head is grey with large red eyes, black sides, and reddish beard. The thorax is dark grey. The legs are dark grey to black and bristly. The wings are clear.
Tabanidae include both Deer Flies and Horse Flies. Deer Flies are smaller than Horse Flies (1/2” long). Their wings are tinted smoky brown or have dark patterns. Their thorax is greenish-yellow with dark stripes. The eyes touch each other on the top of the head in males and are separated in the females.
Adult Horn Flies are slender, 3/16” long and are about 1/2 the size of a typical House Fly. They are charcoal gray in color, with 2 dark stripes on the thorax, and a few diffuse spots on the top of the abdomen. They have an extended, piercing proboscis and long palps.
Stable Flies resemble House Flies with their dull appearance and their 4 dark stripes on the upper body. These flies are 3/16”-5/16” long. The abdomen has dark spots. “Checkerboard” markings are obvious on the topside of the abdomen. Stable Flies have a needle-like, stiff, piercing mouthpart that protrudes forward below their head.
House Flies are 3/16”-5/16” in length and black with 4 dark stripes on the thorax. The abdomen is greyish or yellowish at the sides and has a dark stripe down the middle. These flies have fleshy sponging mouthparts and do not bite. The eyes are reddish and are well separated in males. The eyes have a golden stripe around the outer edge. The legs are hairy with adhesive pads and sharp claws. The wings are clear and are held level and straight back.