Filth Flies
 

House Fly, Musca domestica Several species of flies can be found in and around homes during the summer months. These medium-sized flies are attracted to human and animal waste and decaying garbage. Because of these habits, they are capable of transmitting filth-related diseases such as diarrhea and dysentery. Distributed throughout the world, the house fly is one of the most common of all insects. Adults are dull, medium-gray flies, 1/6- to 1/4- inch long with four dark stripes on the thorax. They have sponging, non-biting mouthparts for sucking up liquefied foods. Female house flies live for three or four weeks and lay batches of 75 to 100 small, white, oval eggs, usually in garbage, but also in manure and decaying vegetation. House flies are strong fliers, and can fly up to 20 miles, although they are found primarily within two miles of the larval food site. When feeding, house flies regurgitate liquid from the stomach to dissolve food, then use their sponging mouthparts to suck it up. They leave fecal spots, or "specks," where they have walked, and in this way may transfer disease organisms to humans and animals. In rural areas, house flies can be a nuisance when they gather on the outside walls of homes and buildings on summer evenings. Blow Fly, Family Calliphoridae Little House Fly, Fannia canicularis The adults of the little house fly are similar to house flies, but they are smaller, from 1/8- to 3/16-inch long, and have more slender abdomens. When at rest, they hold their wings together over their backs. Like the house fly, they have sponging mouthparts. Adult females commonly lay eggs in animal and human excrement, and on decaying organic matter, including dead insects and animals. The life cycle requires four weeks or less. Males often seek shade indoors, where they may hover in rooms for long periods. Little house flies may be a nuisance up to two miles from the breeding site. Stable Fly, Stomoxys calcitrans Stable flies resemble house flies but have "checkerboard" markings on the abdomen and bayonet-like mouthparts used to pierce skin and suck blood. They are about 1/4-inch long, and are sometimes called "biting house flies." Both sexes can inflict a painful bite, feeding on the blood of warm-blooded animals including humans, horses and cattle. Dogs kept in kennels outdoors may be bitten severely, especially on legs and ear tips. Stable flies are able to bite through clothing, and particularly attack the ankles. They are strong fliers, and may fly long distances for a blood meal. Female stable flies can lay 400 or more eggs during their lifetime, in decaying organic matter such as soiled animal bedding or rotting grass clippings. The entire life cycle may take from 17 to 50 days, depending on food supply and weather conditions. In the United States, stable flies are important in causing economic losses in feeder cattle. False Stable Fly, Muscina stabulans False stable flies do not bite, but have sponging mouthparts. They are similar to house flies, but are about 3/8-inch long and have a dull reddish mark on the back. Females lay eggs in tainted foods, excrement, the dead bodies of insects, snails and vertebrates, and are sometimes parasitic on nestling birds. The life cycle may take five to six weeks.