In the fall when I sat outside the flies would bite, they also bite the horses to the point of open wounds (which we of course took care of). they are called
biting flies/stable flies for a reason. They are not horseflies. I lived in CT at the time and have been bothered by them here and there in FL.
They look like houseflies and frankly who looks at the fly to identify it when it is biting you?
Look up biting flies. This is what I found for them:
http://edis.ifas.ufl.edu/ig081
Stable Fly
The stable fly (Figure 3), also known as the dog fly, is a blood-sucking pest that closely resembles the house fly. It is similar to the house fly in size and color, but is easily recognized by its large, piercing mouthparts, which project forward from the head. Unlike many blood-feeding insects, such as mosquitoes, both sexes of the stable fly feed on blood.
The stable fly is a common pest of man and animals throughout the world. Stable flies are strong fliers that can travel up to two miles in search of a blood meal. Because they are persistent and easily interrupted during feeding, they often attack more than one host, increasing the potential for disease transmission. Although stable flies may be mechanical vectors of several animal diseases, they are not known to play a significant role in spreading human pathogens.
In Florida, cattle persistently attacked by stable flies feed less efficiently, resulting in reduced weight gain and milk production. In addition, losses to the Florida tourism industry have occurred when large stable fly populations appear on the Gulf Coast, driving away beach-goers.
After acquiring several blood meals over the course of three to five days, females will mate and develop a batch of eggs. At this time, the female stable fly will seek out areas such as soiled animal bedding, spilled animal feeds, compost piles, and even seaweed deposits along beaches to deposit her eggs. Once an area is located, the female will crawl into the loose material, laying eggs sporadically as she moves. Each female will live for 20 to 30 days as an adult, laying between 500 to 600 eggs during her lifetime. The eggs hatch in 24 to 48 hours, and the larvae develop for a period of 14 to 26 days. The average stable fly life cycle is 28 days and can vary from 22 to 58 days, depending on weather conditions.
Also this:
http://www.ext.colostate.edu/PUBS/insect/05582.html
Stable Fly, "Biting House Fly"
The stable fly (Stomoxys calcitrans) is a blood-feeding pest known to attack almost any kind of warm-blooded animal. It is a major pest of confined livestock throughout the world, including Colorado. It looks like the common house fly except that its mouthparts are adapted for biting and sucking blood. The stable fly feeds by inserting its proboscis (beak) through the skin and then sucking blood from its host. Females can live up to a month and may require several blood meals during this period in order to continue laying eggs. It is a daytime feeder, with peak biting occurring during the early morning and late afternoon. Stable flies prefer to attack people around the ankles. It does not appear to be an important vector of any human diseases.
The immature stable fly (maggot) can be found breeding in many kinds of moist, decaying organic matter, including animal bedding, lawn clippings, and compost. The variety of breeding sites, and the fact that the adults fly several miles to feed but spend little time on the host, make it difficult to manage stable flies. Little can be done except to use repellents and protective clothing. Specific techniques have been developed for managing stable flies in confined livestock operations. These are especially important if the livestock operation is serving as a source of stable flies for nearby residential areas.
So now I can relax (and find some other detail to stress about...)
