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common name: House fly

scientific name: Musca domestica Linnaeus, (Insecta: Diptera: Muscidae)


Distribution and importance

Life cycle and description



The housefly,Musca domestica, is a well-known cosmopolitan pest of both farm and home. This species is always found in association with humans or activities of humans. This is the most common species found on hog and poultry farms, horse stables, and ranches. Not only are they a nuisance, but they also can transport disease-causing organisms. Excessive fly populations are obnoxious to farm workers, and when there are nearby human habitations a public health problem is possible.

More than 100 pathogens associated with the house fly may cause disease in humans and animals, including typhoid, cholera, bacillary dysentery, tuberculosis, anthrax ophthalmia and infantile diarrhea, as well as parasitic worms. Pathogenic organisms are picked up by flies from garbage, sewage and other sources of filth, and then transferred on their mouthparts and other body parts, through their vomitus, feces and contaminated external body parts to human and animal food.

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The housefly has a complete metamorphosis with distinct egg, larva or maggot, pupal and adult stages. The housefly over winters in either the larval or pupal stage under manure piles or in other protected locations. Warm summer conditions are generally optimum for the development of the house fly, and it can complete its life cycle in as little as seven to ten days, and as many as 10 to 12 generations may occur in one summer.

Egg: The white eggs, about 1.2 millimetres in length, are laid singly but pile up in small masses. Each female fly can lay up to 500 eggs in several batches of about 75 to 150 eggs, each over a three to four day period. The number of eggs produced is a function of female size, which is principally a result of larval nutrition.

Larva: The mature larva is 3 to 9 millimetres long, typical creamy whitish in color, cylindrical but tapering toward the head. The head contains one pair of dark hooks. The posterior spiracles are slightly raised and the spiracular openings are sinuous slits that are completely surrounded by an oval black border. The legless maggots emerge from the eggs in warm weather within eight to 20 hours, and they immediately feed on and develop in the material where the eggs were laid. The full-grown maggots have a greasy, cream-colored appearance and are 8 to 12 millimetres long. The larvae go through three instars. When the maggots are full-grown, they crawl up to 50 feet to a dried, cool place near breeding material and transform to the pupal stage. High manure moisture favors the survival of house fly larvae.

Pupa: The pupae are dark brown and 8 millimetres long. The pupal stage is passed in a pupal case formed from the last larval skin that varies in color from yellow, red, brown, to black as the pupa ages. The emerging fly escapes from the pupal case through the use of an alternately swelling and shrinking sac, called the ptilinum, on the front of its head that it uses like a pneumatic hammer.

Adult: The housefly is 6 to 7 millimetres long, with the female usually larger than the male. The eyes are reddish and the mouthparts are sponging. The thorax bears four narrow black stripes and there is a sharp upward bend in the fourth longitudinal wing vein. The abdomen is gray or yellowish with dark midline and irregular dark markings on the sides. The underside of the male is yellowish. The sexes can be readily separated by noting the space between the eyes, which in females is almost twice as broad as in males.

The housefly is often confused with the stable fly, Stomoxys calcitrans (Linnaeus), and the false stable fly, Muscina stabulans (Germar). All three are in the same family.

Adults usually live 15 to 25 days. The potential reproductive capacity of flies is tremendous, but fortunately can never be realized. It has been stated that a pair of flies beginning operations in April may be progenitors, if all were to live, of 191,010,000,000,000,000,000, flies by August.

Adults suck liquids containing sweet or decaying substances. Larvae feed on moist food rich in organic matter. Although they are attracted to a variety of food material, houseflies have mouthparts that allow them to ingest only liquid materials. Solid materials are liquified by means of regurgitated saliva.

The flies are inactive at night, with ceilings, beams and overhead wires within buildings, trees, and shrubs, various kinds of outdoor wires, and grasses reported as overnight resting sites. In poultry ranches, the outdoor aggregations of flies at night are found mainly in the branches, and shrubs, whereas almost all of the indoor populations generally aggregated in the ceiling area of poultry houses.

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Flies commonly develop in large numbers in poultry manure under caged hens, and this is a serious problem requiring control. The control of Musca domestica is vital to human health and comfort in many areas of the world. The most important damage related with this insect is the annoyance and the indirect damage produced by the potential transmission of more than 100 pathogens associated with this fly.

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