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.
There are many kinds of Dung Flies but the most striking is the yellow Dung Fly. This bright yellow, hairy fly is about 3/8” in length. It has dark bristles on long slender legs.Dung Flies breed in cow, horse, pig, and sheep dung. The larvae of some species live in decaying plant material and can be very abundant in rotting vegetation and mud along shorelines. Most of the small black flies that fly up if you disturb a fresh cow pat are Dung Flies. The common yellow Dung Fly is a typical example of this family and, although their larva feed on the dung, the adults are predatory and feed on other flies which have come to the dung to feed.
Adult Flesh Flies are greyish with 3 black stripes running the length of the top surface of the thorax (just behind the head). They have a light and dark checkerboard pattern on the abdomen and are about ½” long. Flesh Flies are similar to Blow Flies in their biology. Most Flesh Flies near the home are attracted to odors of decay. They breed in manure, decaying vegetation and animal flesh or meat. The female deposits live larvae on fresh animal carcasses and on dead snails and large insects.
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.
Cluster Flies closely resemble House Flies, but they are usually larger (3/8"-1/2") and have a yellowish sheen on the thorax. With a mostly black body, their thoracic hairs are short, curly, and yellow to golden. They have tufts of crinkly yellow-orange hairs where their wings attach to the thorax. Older specimens may have some of the yellow thoracic hairs rubbed off. The wings often overlap at their tips when the fly is resting.
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.
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