There are many species of Horse Fly in different genera. Many are large with colourful or patterned compound eyes. One thing they have in common - the female needs blood to make her eggs, like the Mosquito, and she bites - like the Mosquito but a lot more painful. Some species prefer horses, cattle or deer but most will take human blood if available. The male doesn't bite.
Another Horsefly - yet to be identified.