I looked them up on google and they look alot like deer flies. As I remember, their bite hurts but I don't remember any lingering consequences. Are you allergic to them? My dad kills them by holding his hand over his head and waiting for them to land, then smacking them. It seems to work for the deer flies. They don't seem to react as fast as a house fly. The flies I remember hurting far worse were the big horse flies. Good luck with your nemisis.