What type of fly bites people the most?

Not many people know that mosquitoes are a type of fly. This particular fly species creates the most recognizable – and deadly – fly bites of all. In fact,mosquitoes are the most deadly animal on the planet,accounting for more deaths than all other animals combined. This is despite the fact that mosquitoes don’t actually take blood meals to survive,but rather to lay eggs more efficiently. Their bites are generally associated with a raised white welt that is often immediately recognizable – and itchy. After a while,it turns into a smaller red bump,sometimes with a black dot in the middle.

Can flies bite if they aren't mosquitoes?

Mosquitoes aren’t the only type of fly that bites. The flies that you see buzzing around horse stables or crawling on your food can also bite,though it depends on the species. Luckily,most of these bites are rarely more than mildly annoying,though it is possible for flies to transmit diseases or cause painful,raised bites.

What types of flies bite people?

Depending on where you live,you will experience different types of biting flies. For example,in tropic and subtropical areas (such as the Southern states in the U.S.),female sand flies bite. These flies measure about one-eighth of an inch,leave tiny red bumps and blisters and can transmit leishmaniasis,a parasitic disease. In regions that have swamps and lakes in wooded lands,deer flies are common biters. Measuring one-fourth to one-half inch long,these flies have green or golden eyes and are particularly bothersome on hot,summer days. Since they use their mouthparts to cut your skin and drink the flowing blood,deer fly bites are painful and can result in the potentially fatal rabbit fever (tularemia). Black flies,horse flies and stable flies can also bite humans with similar results. Luckily,the common house fly doesn’t bite,but does pose a health risk due to contamination.

What if you don't see any flies?

Flies aren’t always slow,large and loud. In fact,you might not even see some flies that bite. Biting midges are commonly referred to as ‟no-see-ums” because,well,it’s rare that you will physically see them. Measuring in at under one-eighth of an inch,these tiny flies are so small that they can get through your typical porch screen. Fine mesh screens work better at keeping these biting pests at bay. Many times,the only sign you’ll get that you’re dealing with no-see-ums are the actual fly bites themselves. Their bites are tiny,but can be painful and very itchy. Worse still,they’re very hard to kill because they’re so hard to see,making these biting flies frustrating and annoying – but at least not deadly.

How can you get rid of biting flies?

Biting flies can be difficult to control,depending on the species. Species such as the black fly,horse fly,deer fly and biting midge breed in swamps,ponds and other ‟mucky” areas. This makes them difficult to reach and in some cases,impossible. For control of these types of flies,a pest management professional is almost always necessary. Stable flies can be easier to manage since they breed in grass clippings,hay residue and decaying crops. Keeping these items to a minimum might control the stable fly population,but only locally. That’s because stable flies can travel more than 100 miles,making it hard to control populations that come from afar.

Can you avoid fly bites?

You can avoid biting flies by knowing what times of the day and year they are most active. No-see-ums are most active at dawn and dusk,especially in the summer. Black flies,deer flies,stable flies and horse flies are most active during the day,with stable flies being prevalent from late fall to January,and deer and black flies abundant all throughout spring. Stay vigilant during these times and keep indoors when you can. If you have to go outside,try to cover up as much skin as possible with clothing,hats,gloves,etc. If you have a large fly population,your first call should be to Terminix® for a free pest estimate. Do flies bite? Absolutely. Should you have to put up with them? No way.

Do Flies Bite? Identifying Biting Flies

Updated: May 23, 2025

If you’ve ever felt a sharp, stinging sensation while outdoors, you may have wondered: Do flies bite? The answer is yes, but only certain types. While many flies are harmless, several species do bite, and some can even transmit diseases. Unlike mosquitoes, which pierce the skin, most biting flies use cutting or scraping mouthparts to tear the skin and feed on blood.

So, why do flies bite? In most species, it's only the females that bite, and they do it to obtain a protein-rich blood meal necessary for reproduction. Flies are attracted to body heat, carbon dioxide, sweat, and movement, all of which make humans and animals ideal targets.

Which kinds of flies bite?

Not all flies bite, but several species are known for their aggressive feeding habits and their painful bites. If you’ve ever spent time outdoors during warmer months, you’ve probably encountered at least one of the following biting flies:

Horse flies: Large (up to one inch), dark-colored flies with powerful wings and green or black eyes. Horse fly bites are very painful since they use scissor-like mouthparts to slice the skin.
Deer flies: Slightly smaller than horse flies, with colorful, patterned wings and bright green or golden eyes. Common in wooded areas near water, their bites can transmit tularemia, also known as rabbit fever.
Black flies: Small, dark flies found near fast-moving rivers and streams. They bite by cutting the skin and feeding on the blood, often leaving itchy, swollen welts.
Stable flies: Resemble house flies but have a piercing proboscis or elongated mouthparts. They are often found near livestock, and their bites are painful and can cause irritation in humans.
Sand flies: Tiny (about one-eighth of an inch), pale flies that are most active at dawn and dusk. Their bites can result in itchy red bumps and may transmit leishmaniasis in some regions.
No-see-ums (biting midges): Extremely small flies that are hard to detect but can deliver surprisingly painful bites, especially near coastal or marshy areas.
Mosquitos: Technically part of the fly family, mosquitoes are the most well-known biting insects. They pierce the skin to draw blood and can spread dangerous diseases like Malaria, West Nile virus, and Zika.

Luckily, common flies like house flies, fruit flies, and most gnats do not bite. They are unsanitary and spread bacteria, but they lack the mouthparts needed to pierce the skin.

What happens when a fly bites?

Fly bites can range from mildly irritating to seriously painful, depending on the species. Most biting flies use blade-like mouthparts to tear through the skin rather than piercing it like a mosquito. The open wound allows blood to flow, which the fly laps up with a sponge-like tongue or proboscis.

Common reactions to fly bites include:

Immediate pain or stinging sensation
Redness and swelling around the bite site
Itchy welts or blisters
Possible allergic reactions, especially with repeated exposure

In most cases, fly bites are more annoying than dangerous. However, some species are capable of spreading diseases or causing secondary infections if the bite is scratched excessively or left untreated. For example, deer flies can transmit tularemia, while sand flies are known to carry parasitic diseases in certain parts of the world.

Not every bite will result in illness, but it’s still important to clean the affected area and monitor it for signs of infection, especially if swelling worsens or symptoms persist.

Preventing fly bites

Avoiding biting flies starts with knowing where and when they’re most active and taking the right steps to protect yourself. Along with preventing flies from invading your space, here’s how you can avoid fly bites:

Stay indoors during peak activity: Most biting flies are active during the day, especially in the warmer months. No-see-ums, however, are most active at dawn and dusk.
Wear protective clothing: Long sleeves, pants, hats, and gloves can limit exposed skin.
Use insect repellent: Products containing DEET, picaridin, or oil of lemon eucalyptus can deter many types of biting flies.
Install window screens: Fine mesh screens can keep flies out of your home, especially in rural or coastal areas.
Clean up potential breeding areas: Stable flies and similar species breed in wet hay, grass clippings, and manure. Eliminating these materials helps control populations.

Controlling biting flies can be difficult, especially since many of them breed in remote, hard-to-reach environments like swamps, wetlands, and compost piles. While stable flies can be locally managed, they’re also capable of traveling more than 100 miles, making full control nearly impossible without expert help.

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