Types of Flies & Mosquitoes: 8 Common Species
Only one pair of flying wings; the hind pair is reduced to tiny knobs. This guide covers the 8 flies & mosquitoes people find most often.
How to narrow it down
Narrow it down with three quick checks. Count the legs: insects have six, spiders and ticks have eight, and centipedes and millipedes have many more. Check for wings, even folded ones. Then compare size against a coin: a US penny is 19 mm across. Our bug identifier tool does this filtering for you.
The 8 bugs
Mosquito
MosquitoCulicidae (e.g. Aedes albopictus)A small, slender fly whose females bite to take blood for egg production. The Asian tiger mosquito is black with white stripes and bites aggressively during the day.
Tell-tale sign: Long, needle-like mouthpart (proboscis). Risk: Mosquito bites itch and, depending on the region, can transmit West Nile, dengue and other viruses.
Horse Fly
Horse FlyTabanus spp.A large, stout fly with huge eyes that pursues people, horses and cattle for blood. Females slice skin with blade-like mouthparts, causing a sharp, painful bite.
Tell-tale sign: Large, heavy body with very large, often iridescent eyes. Risk: Horse fly bites are painful and can swell; they rarely transmit disease to people in the US.
Blow Fly
Blow FlyLucilia sericataA shiny, metallic green or blue fly that lays eggs on dead animals, meat and garbage. A sudden swarm indoors often signals a dead mouse or bird in a wall or attic.
Tell-tale sign: Metallic green, blue or bronze body. Risk: Blow flies don't bite but can carry bacteria from rotting material.
Drain Fly
Drain FlyClogmia albipunctataA small, fuzzy, moth-like fly that rests on bathroom walls near sinks, tubs and floor drains. Its larvae live in the slimy film inside drains.
Tell-tale sign: Fuzzy, gray, leaf-shaped wings held roof-like over the body. Risk: Drain flies don't bite and aren't known to spread disease in homes.
Fruit Fly
Fruit FlyDrosophila melanogasterA tiny, tan fly with bright red eyes that hovers over ripe fruit, drains, trash and spilled drinks. It can go from egg to adult in about a week.
Tell-tale sign: Very small tan body with bright red eyes. Risk: Fruit flies don't bite; they can carry bacteria from trash onto food.
Fungus Gnat
Fungus GnatBradysia spp.A tiny, dark, mosquito-like fly that hovers around houseplants and windows. Its larvae live in moist potting soil and feed on fungi and roots.
Tell-tale sign: Delicate dark body with long legs and antennae. Risk: Fungus gnats don't bite; larvae can damage seedlings and young roots.
House Fly
House FlyMusca domesticaThe most common fly in homes, a dull gray fly with four dark stripes on its thorax. It breeds in garbage, manure and rotting food and lands on nearly everything.
Tell-tale sign: Four dark lengthwise stripes on a gray thorax. Risk: House flies don't bite, but they can carry bacteria that cause food poisoning.
Crane Fly
Crane FlyTipula spp.A huge, fragile, long-legged fly often mistaken for a giant mosquito. Adults barely feed, and the larvae, called leatherjackets, eat grass roots.
Tell-tale sign: Extremely long, thin legs that detach easily. Risk: Crane flies cannot bite or sting and do not eat mosquitoes, despite the nickname mosquito hawk.
Which ones should you worry about?
2 of the 8 bugs in this guide can bite or sting. The ones to take seriously are mosquito. The rest are harmless or simply a nuisance.
Comparison at a glance
| Mosquito | Horse Fly | Blow Fly | |
|---|---|---|---|
| Group | Flies & Mosquitoes | Flies & Mosquitoes | Flies & Mosquitoes |
| Scientific name | Culicidae (e.g. Aedes albopictus) | Tabanus spp. | Lucilia sericata |
| Size | 3–6 mm | 10–30 mm | 8–12 mm |
| Colors | Black, White and Gray | Black, Brown and Gray | Green, Blue and Metallic |
| Legs | 6 legs | 6 legs | 6 legs |
| Wings | Yes | Yes | Yes |
| Bites or stings | Bites | Bites | No |
| Risk | Health risk | Can bite or sting | Nuisance |
| Key feature | Long, needle-like mouthpart (proboscis) | Large, heavy body with very large, often iridescent eyes | Metallic green, blue or bronze body |
Frequently asked questions
What is the most common one?
Among the bugs in this guide, the mosquito and horse fly are the ones people ask about most.
Which of these are dangerous?
Mosquito can be medically significant.
How can I identify a bug I found?
Use the free bug identifier tool: choose the number of legs, wings, main color, size and where you found it, and it will list the closest matches.