The 10 Most Common Types of Flies in the U.S.
Updated: Jan. 03, 2024
The swatting season is here! We've got the buzz on the types of flies you're likely to encounter this summer.
Housefly
Known as a total nuisance in and around the home, the Musca domestica Linnaeus, more commonly known as the housefly, is the most widespread, bi-winged insect in the United States.
What they look like
Typically from one-eighth to one-quarter inch long, the housefly features a hairy, oval thorax bearing black stripes, a yellowish-gray abdomen and two glossy gossamer wings that extend beyond the torso. Their most prominent feature? Their big, bulging red eyes.
Where to find them
The housefly inhabits a wide range of climates and environments, from tropical to arid and urban to rural, all around the world.
What to do if you see one
Apart from vigorously swatting or shooing them away, we recommend setting up traps to keep houseflies from disrupting your fun and cutting down on the potential spread of food-borne diseases.
According to the Centers for Disease Control and Prevention (CDC), “Each housefly can easily carry more than one million bacteria on its body. Some of the disease-causing agents transmitted by houseflies to humans are Shigella spp. (dysentery and diarrhea = shigellosis), Salmonella spp. (typhoid fever), Escherichia coli, (traveler’s diarrhea) and Vibrio cholera (cholera).”
How to prevent them
Attracted to most organic matter from food to feces, hungry houseflies have been known to travel up to 20 miles for a good meal. Removing trash frequently and sealing garbage cans and compost bins goes a long way.
Did you know? The taste receptors of a housefly are in their feet, which are 10 million times more sensitive to sugar than the human tongue.
Horsefly
Horseflies are champs at pestering livestock. The male horsefly feeds mainly on pollen and plants. However, the bitey female is more predatory, using her compound eyes to keenly choose her prey. When she finds a victim, she goes in with her sharp mouthparts to feast on the blood of larger warm-blooded animals like cows and horses.
What they look like
The hefty horsefly can range from 3/8-in. to one inch long. They have gray or black bodies with large green or purple iridescent eyes.
Where to find them
There are 160 species of horsefly. Most live near bodies of water (which often serve as breeding sites), grasslands and damp woodland habitats all throughout North America.
Because they’re drawn to light, horseflies congregate around windows. They’re most evident on hot, windless, sunny days. You might run across them resting on shady paths and rural roads, especially in wooded areas, waiting for their potential prey to trot along.
What to do if you see one
A horsefly bite can be quite painful and could trigger allergic reactions, so it’s best to steer clear and avoid aggressively swatting at them. When outdoors, for some people, insect repellant will help keep them away.
How to prevent them
To exclude horseflies from your indoor spaces, install or repair screens on all doors and windows.
Did you know? Horseflies instinctually attack large, moving objects and prefer dark over lighter-toned animals.
Fruit or Vinegar Fly
Petite to the point of being nearly invisible, fruit flies (aka vinegar flies) are all about decaying, rotting and overripe fruit and vegetables. These airborne pests live an average of only 20 days. But during that time they can be extremely reproductive, laying as many as 500 eggs at one time.
What they look like
The fruit fly has a translucent yellowish-brown or tan body, red eyes and six legs.
Where to find them
Hovering over your brown bananas or a bowl of soft tomatoes. Except for cold climates, fruit flies can be found everywhere.
What to do if you see one
You won’t likely see just one fruit fly, but rather a whole slew of them. As soon as you do, make a simple fruit fly trap.
How to prevent them
To keep fruit flies at bay, immediately clean up any spills on the counter, wash produce when you bring it home from the market, and keep ripening fruit covered or stored in the fridge.
Did you know? Fruit flies make excellent subjects in laboratory studies because they share the same DNA as most living organisms.
Drain Fly
Did you know the sludge that accumulates in the lining of your plumbing is considered a gourmet meal to drain flies (aka moth flies or sewer gnats)?
What they look like
Drain flies are fuzzy and range from light tan to black, making them look more like moths than flies. They measure around three-sixteenths inch long with oversized, oval wings.
Where to find them
It’s estimated there are nearly 3,000 identified species of drain flies worldwide. Living up to its name, the drain fly can live pretty much anywhere water accumulates and stagnates. Think kitchen and bathroom sinks, shower and tub drains, leaky sewers and septic tanks. You’re also likely to find drain flies in wet, shady areas where mold and algae grow.
What to do if you see one
Buy a brush to remove bacteria-laden gunk that builds up in your plumbing pipes. Besides eliminating germs, you’re getting rid of a drain fly’s ongoing source of food.
How to prevent them
Clean your drains once or twice a week by pouring boiling water down the drain. You can also try periodically using a mixture of 1/2-cup baking soda, 1/2-cup salt and one cup apple cider or white vinegar. After pouring the concoction down the drain, let it sit overnight, then flush in the morning with hot water.
Warning: Never put insecticides or bleach down a drain. These products could severely damage the sewer system as well as contaminate the water supply.
Phorid Fly
If you’ve never heard of a phorid fly (aka humpback fly), you’re not alone. These zig-zaggers fly about in an irregular pattern, which explains why some people call them scuttle flies.
What they look like
Around the same size as the fruit fly (above), the phorid fly features a bulge on its back and comes in a range in colors — black, brown, yellow or some combination thereof. It also has spiky hairs on its little face and a pair of long, flat, back legs sprouting from behind. Their most identifying feature: heavy veins near the front margin of the wings.
Their eggs have been described as boat-shaped, with an average length of less than one-quarter inch. The eggs can vary in color from white to off-white to gray. If you’ve ever seen a maggot, that’s what you’re looking for.
Where to find them
They’re also called coffin flies because they lurk in musty mausoleums devouring decomposing flesh, as well as inside dark, smelly dumpsters where organic materials are most abundant. They’re found worldwide, with the greatest numbers in tropical climates.
What to do if you see one
You don’t want these flies hanging around. Although rare, some types of parasitic phorid flies can cause gastrointestinal myiasis, when fly eggs or larvae deposited in food enter a human’s gastrointestinal tract. Infested people can experience abdominal pain, vomiting and diarrhea.
How to prevent them
The best way to control phorid flies is to stop their eggs from hatching, pronto. Keep dumpster and other garbage receptacle lids closed tightly. Also, keep a clean house. If you feel like you’re overrun by these critters, it might be wise to call in a pest control specialist for this job.
Fungus Gnat
If you didn’t already know, fungus gnats are actually members of the “true fly” family. Annoying as all get-out, these small, dark flying insects are partial to over-watered houseplants, algae, mushrooms and soggy leftover potting soil.
What they look like
Adult fungus gnats have thin legs with segmented antennae not that much longer than their heads. Averaging about one-half inch long, their clear wings are light gray with a “Y”-shaped wing vein.
Where to find them
Another flying pest that loves the light, you’ll find them happily skittering around windows. They live on every continent in the world except Antarctica.
What to do if you see one
A fungus gnat poses no harm to humans and doesn’t carry diseases. Even if it reproduces in your indoor plants, it rarely causes damage, so you really don’t have to do anything.
To determine if you have a fungus gnat problem, inspect your property and home for adult gnats napping in plants and soil, or on windows or walls. Because they’re more annoying than anything else, you might want to employ gnat traps to keep them under control.
How to prevent them
Because fungus gnats thrive in wet conditions, let the surface of the soil in containers dry before re-watering. And make sure your pots have good drainage.
Crane Fly
From a distance, crane flies (aka daddy longlegs or mosquito hawks) are regularly confused with mosquitoes, though they’re significantly larger and don’t actually pierce human flesh.
What they look like
Ludicrously long-legged, crane flies are gray to brown, with long, thin bodies and wings that appear almost smokey.
Where to find them
Found throughout the world, crane flies gravitate toward wet areas near lakes, rivers and streams. In summer, porch and patio lights attract them. Preferring heavily vegetative habitats, they’re commonly found in lawns and turf. They aren’t big fans of extremely cold or hot climates.
What to do if you see one
Crane flies are about the most harmless flying insect out there. In large numbers, however, they can damage or kill patches of lawn. To eliminate crane flies and their larvae, apply an insect growth inhibitor made for lawns and turfgrass around your property.
How to prevent them
The best way is maintaining a healthy and vibrant turf or lawn. This entails improving drainage and making sure the soil is dry and aerated.
Did you know? Birds, bats and frogs like to eat crane flies!
Blowfly
The blowfly (aka bottle fly) has an extremely high gross factor. Blowflies produce larvae (maggots) that devour the decaying corpses of humans and animals.
What they look like
Slightly larger than a housefly, the blowfly is distinguishable by shiny, metallic blue, green or black bodies with bristly hairs.
Where to find them
Existing in every geographical area of the world, they especially thrive in humid, wet, tropical areas where loose, damp soil or decaying material is present. (It’s the best environment for their larvae to develop.) Agile fliers, the blowfly loves filth, so it’s no wonder they’re especially drawn to excrement.
What to do if you see one
You can try using bombs, foggers or insecticide sprays, but keep in mind they will not affect flies that haven’t hatched yet.
How to prevent them
Rachel Maccini, coordinator of pesticide safety education at the University of New Hampshire Extension, advises removing household garbage every four to five days in the summer to prevent flies from successfully breeding.
Also, because these flies are known to reproduce in animal waste, be sure to keep pet litter boxes and/or the yard cleaned up after animals defecate there.
Did you know? The maggots of blowflies (known as “gentles”) are sometimes used as fishing bait.
Mosquito
The word “mosquito” in Spanish means “little fly.” Apart from their cute moniker, mosquitoes are arguably one of the most hated winged insects on the planet. A member of the true fly Diptera family, mosquitoes are associated with water and warm temperatures.
What they look like
Mosquitoes are slender, spindly creatures covered in scales. They have fine, thread-like legs with feathery antennae bushier in the male than the female. And speaking of females, the adult gender pierces flesh using its spongy mouthpart, which acts like a straw to suck the blood of its victims.
Where to find them
There are more than 3,500 kinds of mosquitoes around the globe, with more than 200 species in the U.S. alone.
What to do if you see one
Break out the citronella! Here are several other helpful tips for repelling mosquitoes this summer, including a chemical-free repellant.
How to prevent them
Some mosquitoes are classified as vectors: An animal, insect or tick that can spread germs and diseases to humans that can make you sick. On their website, the CDC lists some of the most serious diseases, including the West Nile, Dengue, chikungunya, Zika and malaria.
Here are seven ways to deter mosquitoes.
Cluster Fly
Large and sluggish, cluster (aka attic) flies love to use your home as a warm place to spend the winter.
What they look like
Closely mimicking the average housefly in size and color, cluster flies average around one-third inch long and are dark gray with bristles on their bodies. What sets them apart? A checkered pattern on their abdomens.
Where to find them
“Cluster flies are thought to be native to Europe and may have found their way to North America in the ballast of ships containing soil and the cluster fly host, earthworms,” according to Penn State Extension.
Cluster flies love hunkering down in attics, under siding, around windows and other crevices. As the temperature warms, they’ll move outdoors, often covering the sunny side of the house.
What to do if you see one
Nothing. Cluster flies don’t damage buildings, furniture, people or pets. If they become a real nuisance, follow these tips for getting rid of them.
How to prevent them
Fortunately, cluster flies do not breed or hatch indoors. And because they’re so slow, they can be easily sucked up with a vacuum cleaner or batted down with a fly swatter.
Pro tip: If you use a vacuum cleaner to pick up cluster flies, remember to remove the bag, seal it and throw it in a bin outdoors. If you don’t, the flies could escape, and you’ll be right back where you started.
Originally Published: June 27, 2023
