Types of Flies

I used to think a fly was a fly until one landed on my arm at a lake and left a welt. That was a deer fly, not the harmless one buzzing around my kitchen. The two looked nothing alike once I paid attention.

Flies are one of the largest insect groups on earth, with more than 150,000 known species. Some are familiar, like the housefly. Others are bright metallic bottle flies, blood-feeding mosquitoes, or long-legged giants. A few bite, a few carry disease, and others turn out to be useful.

Below you will find the main types of flies, what sets each one apart, and where they live. The charts group them by family, then by size, biting habits, and habitat. You can match a fly to its name in a few steps.

Table of Contents

Types of flies and their names

All true flies belong to the order Diptera. The name means “two wings,” and that is the key trait. A fly has one pair of wings. Its hindwings have shrunk into tiny knobs called halteres, which help it balance in flight.

Scientists sort flies into families by body shape, mouthparts, and life cycle. A few families cover most of the flies you will meet. The table below lays out the main ones so you can place a fly before you name it.

Family	Scientific family	Key trait	Examples
House & stable flies	Muscidae	Drab gray bodies; the classic indoor fly	Housefly, stable fly
Blow & bottle flies	Calliphoridae	Shiny metallic blue or green	Blue bottle, green bottle
Horse & deer flies	Tabanidae	Large, with painful biting mouthparts	Horse fly, deer fly, yellow fly
Mosquitoes	Culicidae	Slender, long legs; females feed on blood	Common mosquito
Hover flies	Syrphidae	Bee or wasp mimics that hover in place	Flower flies, drone fly
Crane flies	Tipulidae	Very long legs; large but harmless	Giant crane fly
Fruit flies	Drosophilidae, Tephritidae	Tiny; drawn to fruit and crops	Common fruit fly, medfly
Robber flies	Asilidae	Bristly aerial predators of other insects	Giant robber fly

Within those families sit tens of thousands of species. The chart below lists common and notable flies, with the family each belongs to, its size and colors, and a feature that helps you tell it apart.

Common fly type	Family	Size	Main colors	Distinct feature	Where found
Housefly	Muscidae	Small	Gray, black	The common indoor pest	Homes & farms
Fruit fly	Drosophilidae	Tiny	Tan, yellow	Drawn to ripe fruit	Kitchens
Blow fly	Calliphoridae	Medium	Metallic blue/green	Feeds on decaying matter	Carrion
Flesh fly	Sarcophagidae	Medium	Gray, striped	Larvae feed on carrion	Garbage areas
Horse fly	Tabanidae	Large	Brown, black	Painful biting mouthparts	Near livestock
Deer fly	Tabanidae	Medium	Yellow, black	Colorful eyes; bites people	Wetlands
Mosquito	Culicidae	Small	Gray, brown	Females feed on blood	Standing water
Crane fly	Tipulidae	Large	Brown	Very long legs; harmless	Gardens & grass
Hover fly	Syrphidae	Small–medium	Yellow & black	Bee mimic; hovers in air	Flowers
Robber fly	Asilidae	Medium–large	Gray, black	Catches prey in flight	Open sunny areas
Botfly	Oestridae	Medium	Hairy brown	Parasitic larvae	Mammals
Tsetse fly	Glossinidae	Medium	Brown	Spreads sleeping sickness	Africa
Black fly	Simuliidae	Tiny	Black	Hump-backed biting fly	Rivers & streams
Sand fly	Psychodidae	Tiny	Pale brown	Can spread leishmaniasis	Tropical regions
Drain fly	Psychodidae	Tiny	Gray, fuzzy	Breeds in drains	Bathrooms
Stable fly	Muscidae	Medium	Gray	Biting housefly relative	Farms
Kissing fly	Rhiniidae	Medium	Metallic	Often mistaken for bees	Tropical habitats
March fly	Bibionidae	Medium	Black	Swarms in spring	Meadows
Dance fly	Empididae	Small	Black, gray	Courtship “dance” flight	Woodland edges
Bee fly	Bombyliidae	Small–medium	Hairy brown	Long proboscis; bee-like	Flower gardens
Scorpion fly*	Mecoptera (not a fly)	Medium	Yellow-black	Tail curls like a scorpion	Forest plants
Phorid fly	Phoridae	Tiny	Brown	Runs in a zigzag	Decaying material
Eye gnat	Chloropidae	Tiny	Black	Drawn to eyes and fluids	Humid climates
Hessian fly	Cecidomyiidae	Tiny	Dark gray	Wheat crop pest	Farm fields
Gall midge	Cecidomyiidae	Tiny	Orange, brown	Forms plant galls	Shrubs & crops
Olive fruit fly	Tephritidae	Small	Brown, clear wings	Olive pest	Mediterranean
Mediterranean fruit fly	Tephritidae	Small	Yellow-brown	Major fruit pest	Orchards
Apple maggot fly	Tephritidae	Small	Black, banded wings	Infests apples	Orchards
Phantom crane fly	Ptychopteridae	Medium	Black & orange	Long, dangling legs	Wet habitats
Fungus gnat	Sciaridae	Tiny	Black	Lives in moist soil	Houseplants
Midge	Chironomidae	Tiny	Gray	Mosquito-like but does not bite	Lakes & ponds
Lovebug	Bibionidae	Medium	Black, red thorax	Flies in mating pairs	Southeast U.S.
Blue bottle fly	Calliphoridae	Medium	Metallic blue	Loud, buzzing flight	Garbage & carrion
Green bottle fly	Calliphoridae	Medium	Metallic green	Used in maggot therapy	Decaying matter
Yellow fly	Tabanidae	Medium	Yellow-orange	Painful bite	Swamps
Window fly	Scenopinidae	Tiny	Black	Found on windows	Indoors
Soldier fly	Stratiomyidae	Medium	Black, metallic	Wasp mimic	Compost & flowers
Black soldier fly	Stratiomyidae	Medium	Black	Key composting species	Organic waste
Kelp fly	Coelopidae	Small	Brown	Lives on seaweed	Beaches
Dung fly	Scathophagidae	Small	Yellow-brown	Lives around manure	Pastures

*The scorpion fly and the “lantern fly” are not true flies. Scorpion flies belong to the order Mecoptera. The name “lanternfly” usually means a planthopper in the order Hemiptera, so the row above lists the phantom crane fly (Ptychopteridae), which is a real fly. True flies all sit in the order Diptera and have a single pair of wings.

Largest fly species

Most large flies live in warm regions and belong to a few heavy-bodied families. The biggest true fly is the mydas fly of Brazil, which can reach a body length of about 7 cm. Crane flies look even larger because of their long legs, though their bodies stay slim.

The table below ranks the largest flies by size. Keep in mind that leg span and body length tell different stories, so a crane fly can span a hand while weighing almost nothing.

Species	Family	Size	Where found
Mydas fly (Gauromydas heros)	Mydidae	Body up to ~7 cm	Brazil
Timber fly	Pantophthalmidae	Body up to ~8 cm	Tropical America
Giant crane fly	Tipulidae	Leg span up to ~10 cm	North America, Asia
Robber fly (large species)	Asilidae	Up to ~3 cm	Open sunny areas
Horse fly	Tabanidae	Up to ~2.5 cm	Worldwide, near livestock

Smallest fly species

At the other end are the phorid flies, fungus gnats, and midges, many smaller than a sesame seed. The smallest known fly is a phorid, Euryplatea nanaknihali, at about 0.4 mm. Its larvae develop inside the heads of tiny ants.

Small flies are easy to overlook, but they matter. Fungus gnats swarm around houseplants, fruit flies appear near ripe produce, and midges rise in clouds over lakes at dusk. Most of them do not bite, even the ones that look like mosquitoes.

Biting flies and disease

This is the part that matters most for health. A small number of flies bite, and a few of those can carry disease. The risk depends on where you are. The same fly can be harmless in one region and a concern in another.

The table below sorts well-known flies by whether they bite and what health concern they raise. For most people, the everyday housefly is a nuisance rather than a danger, though it can still spread germs from waste to food.

Fly	Does it bite?	Main health concern
Mosquito	Females bite	Can spread malaria, dengue, Zika, and West Nile, depending on the region.
Tsetse fly	Bites	Spreads African sleeping sickness in parts of sub-Saharan Africa.
Sand fly	Bites	Can spread leishmaniasis in tropical and subtropical areas.
Black fly	Bites	Spreads river blindness in parts of Africa and Latin America.
Horse & deer fly	Bites	Painful bites; they rarely spread disease to people.
Housefly	Does not bite	Carries germs on its body and can contaminate food.
Crane fly	Does not bite	Harmless. It does not bite, sting, or carry disease.

Helpful flies you might not expect

Not every fly is a pest. Flies are the second most important pollinators after bees. Hover flies do much of that work in gardens, and their larvae eat aphids. That makes them a quiet ally for anyone growing vegetables.

Other flies clean up after us. Black soldier fly larvae break down food waste and manure, and farmers now raise them as animal feed. Green bottle fly maggots are even used in medicine to clean dead tissue from wounds, a practice called maggot therapy.

Common flies around the home

A few flies turn up indoors more than any others. The housefly comes through open doors and breeds in waste. Fruit flies appear near ripe or fermenting fruit, while drain flies and fungus gnats breed in damp drains and potted soil.

Most home infestations trace back to moisture and food. Clear the breeding source and the flies fade within a week or two. A drain fly problem points to a slow or dirty drain, and a cloud of fungus gnats usually means a houseplant is being overwatered.

Types of flies by habitat

Where you are shapes the flies you see. Kitchens draw houseflies and fruit flies, farms draw biting stable flies, and wetlands fill with mosquitoes and midges. The table below pairs each habitat with the flies you are most likely to find there.

Habitat	Flies you’ll find there
Homes & kitchens	Housefly, fruit fly, drain fly, fungus gnat, phorid fly
Farms & livestock	Stable fly, horse fly, dung fly, deer fly
Water & wetlands	Mosquito, midge, black fly, crane fly
Gardens & flowers	Hover fly, bee fly, soldier fly
Carrion & waste	Blow fly, blue bottle, green bottle, flesh fly, black soldier fly

FAQs

How many types of flies are there?

There are more than 150,000 known fly species in the order Diptera, and scientists keep finding more. Most fall into a handful of families you can learn to recognize.

What makes an insect a true fly?

A true fly has one pair of wings, with the hindwings shrunk into tiny balancing organs called halteres. Mosquitoes, midges, and gnats are all true flies, while scorpionflies and lanternflies are not.

What is the largest fly?

The mydas fly, Gauromydas heros, is the largest. Its body can reach about 7 cm, with a wingspan near 10 cm, and it lives in Brazil.

What is the smallest fly?

The smallest is a phorid fly, Euryplatea nanaknihali, at about 0.4 mm. That is smaller than a grain of salt.

Which flies bite people?

Several flies bite people: mosquitoes, horse flies, deer flies, black flies, sand flies, stable flies, and tsetse flies. With mosquitoes, only the females bite.

Do crane flies bite or sting?

No. Crane flies look like giant mosquitoes, but they do not bite, sting, or carry disease. The adults barely feed at all.

Are any flies helpful?

Yes. Hover flies pollinate plants, and their larvae eat aphids. Black soldier flies break down waste. Green bottle fly larvae are even used to clean wounds, a practice called maggot therapy.