Two plants that eat flies are the Sundew and Venus fly trap. There are many kinds of horseflies. Some varieties are clegs, stouts, breeze-flies, dunflies, and more. They arrive very quietly and you may never see their sinister look. You will be unaware of their presence until you feel the pain of their bite.
Clegs attack around the arm or wrist.
The brightly colored females attack the head and the neck. Deer flies like to bite around the forehead and the eyebrow because they are attracted to the sweat. If they bite around the eyebrow it can cause so much swelling you can't see. Horseflies cause a lot of cow's pain, loss of blood, reduced grazing time, and a smaller amount of milk production.