Fly Identification

Identifying what kind of fly is buzzing around in your home or business can be difficult since there are so many kinds. Often, it’s easiest to identify them based on the area they’re frequenting. There are many different kinds of flies that could be attracted to things on your property. Here’s how you can identify some of the most common ones.

House Flies

Physical Characteristics
  • Size: 1/8-1/4” long
  • Color: Gray with four black stripes on the thorax
  • Body: Slightly hairy with a pair of wings, compound red eyes that give them wide vision, no teeth or stinger

The house fly, which is the most common type found in homes throughout America, is characterized as a large fly. House flies will feed on just about anything, from feces to human food. They can only feed on liquids, however, due to the structure of their mouthparts. If they find a solid piece of food, they must regurgitate digestive fluids onto it to break it down and suck it up. As a result of their feeding behaviors and tendency to inhabit filth-ridden places, house flies can easily contaminate food and spread over 100 different pathogens, including malaria, salmonella, typhoid, and tuberculosis. Adult house flies can live 15-25 days, and usually lay 350-900 eggs, which look like grains of rice, in their lifetimes.

Fruit Flies

Physical Characteristics
  • Size: About 1/8″ long. Many are small enough to be able to penetrate regular mesh screening.
  • Color: Tan to brownish yellow or brownish-black. Eyes usually red.
  • Body: Small and oval in shape with short, bristly antennae, red eyes, no teeth or stinger

Fruit flies, another common type found in homes throughout America, are considered small flies. They hover in small circles searching for food, primarily fermenting or sugary foods like fruits, vegetables, and sweet drinks. They are especially attracted to rotting or expired food. They can also be found in garbage bins, refrigerators, compost piles, discarded dishes and bottles, and spilled liquid. Any place where yeast, sugar, and fermentation are present, fruit flies may find a feeding and breeding site. Similar to house flies, they can transmit a wide variety of diseases and are often responsible for food contamination.

Adult fruit flies can live 25-30 days and are known for their rapid reproduction, which can become an infestation in a short period of time. Females lay about 500 eggs at a time. They will lay their eggs in just about any place they can find, including dirty dishcloths, mop heads, fruit bowls, and buckets of stagnant water.

Horse Flies

Physical Characteristics
  • Size: About ⅜-1⅛“ long
  • Color: Gray or blackish body with dark or semi-dark wings, large eyes that are usually green or purple, horizontal stripes
  • Body: Stout-bodied without bristles, large translucent wings, biting mouthparts

Horse flies are common in wooded areas near bodies of water with livestock or animals nearby. They are considered large flies, and are fast and strong fliers capable of traveling over 30 miles to find food, though they generally don’t widely disperse. Males feed on nectar, but females require a blood meal in order to lay eggs, so they will find animals to feed on, which can include humans. Their bites are typically painful since horse fly mouthparts are built for tearing and lapping instead of mosquito-like sucking. They may even pursue targets, especially dark-colored objects. Their bites may lead to allergic reactions, but they are not known to transmit pathogens or disease. Horse flies usually lay their eggs in bodies of water and are especially known to congregate on hot, windless days.

Blow/Bottle Flies

Physical Characteristics
  • Size: About ⅛-⅝” long
  • Color: Metallic blue, green, or bronze, or are shiny black
  • Body: Similar to house flies with hairy bodies and sponge-like mouthparts, and large translucent wings.

Blow/bottle flies are considered large flies and can be slightly larger than house flies. They are primarily scavengers, feeding on and laying their eggs in meat or animal carcasses, but also in animal excrement and garbage. Dead animals are the usual source of flies within a structure, while dog excrement and garbage are common outdoor sources. Their maggots resemble grains of rice. If a blow fly or bottle fly gets into an open wound, it may transmit pathogens and cause disease.

Drain Flies

Physical Characteristics
  • Size: 1/16-3/16” long, may be able to get through door or window screening
  • Color: Pale yellowish to brownish-gray to black
  • Body: Hairy with broad wings, no stinger or teeth

Also known as moth, filter, or sewer flies, these small flies get their name from their hairy, fuzzy appearances and their tendency to develop in pipes, sewers, and drain areas where stagnant and dirty water is present. They fly in short hops and hover above drains, but are rather weak in extended flight. Females lay 30-100 eggs at a time in masses on the film that covers water-free drains and filters of sewage treatment plants. Larvae feed on the algae, bacteria, fungi, and sludge of the filmy substance that forms in these locations.

Drain flies aren’t known to transmit significant disease but can be annoying to deal with if cleaning in areas where they are present.

Fungus Gnats

Physical Characteristics
  • Size: 1/32-7/16” long, usually able to fit through door and window screening
  • Color: Usually black, sometimes brownish or yellowish
  • Body: Small and dark-colored with dark wings, long threadlike antennae, no stinger or teeth

Fungus gnats are small flies named for their tendency to nest in excrement, fungi, and decaying vegetation. They are small, slender and long-legged, and look similar to mosquitoes. These flies tend to be found in shaded, moist areas, though adults are attracted to light and may gather at windows. They may also breed in overwatered potted plants, mulch, and overwatered lawns. Like other small flies, fungus gnats are not dangerous, just annoying.

Fly Life Cycle

Most flies start out as maggots, small and pale in color, whether birthed or hatched. They will consume food from where their eggs are laid, whether it be decomposing food or plant matter, and shed several times until they grow fully into flies. They typically grow into adults over the course of a few days to a couple of weeks, and from there will begin the process again.

If you are experiencing problems with flies in your house, it’s important to do something about them soon, as many types can ruin food supplies and pass on disease. Learn how to treat a fly infestation on our website or contact us today for solutions!

Contact Us!