Although most people can recognize a bee, hornet, or wasp as being a risk for stinging, many perceive flies as harmless. However, there are several types of biting fly.

Although not all flies bite, those that do can be an irritation and danger to some people.

This article will describe different flies that bite and how to recognize their bites, as well as some potential treatment options.

There are six of biting fly in the United States.

Some of these flies may have variations that are similar in appearance yet do not bite.

Most of the flies in this article do not cause harm other than the bite itself, though some can transmit disease or cause severe allergic reactions.

These six biting flies are:

Biting midges

Biting midges are very small flies, usually no larger than 1/32 of an inch. People may also call them no-see-ums, punkies, or gnats.

They do not transmit disease but can cause small, itchy bites.

Black flies

Black flies are that have a humpbacked appearance. Some people may also call them buffalo gnats.

They do not transmit diseases to humans, but they can cause severe allergic reactions in humans and livestock.

Examples of reactions include swelling, bleeding, and itching. They will usually bite the skin on a person's head.

Deer flies

These medium sized flies normally appear in the spring and are usually the size of a housefly.

They have and are predominantly either yellow-black or brown.

Deer flies can transmit a disease called tularemia, or rabbit fever, to humans.


Horseflies are large. They may have green heads or be completely black. They usually live near water or other warm, wet locations.

Their bites do not transmit diseases but can be painful due to how they bite the skin.

Sand flies

These tiny, worm-like flies are small and usually brown to gray. Although most do not transmit disease, there is a subset of sand flies in Texas that can transmit a severe condition called cutaneous leishmaniasis.

Stable flies

Stable flies are small and gray. They have several stripes on their bodies. They usually appear in the late summer to fall, and they typically bite in the morning or late afternoon.

Stable flies tend to bite people's ankles. Doctors do not think they can transmit diseases.