The deer fly (Chrysops callidus) is a member of the horse fly family (Tabanidae). The females possess sharp mandibles which they use to inflict painful bites to obtain a blood meal.
Unlike mosquitoes, these flies seem to enjoy the sunshine and heat of the day. Their method of attack is a repeated landing on exposed skin especially the back of the neck and face. Eventually they find a safe landing spot and make a cross incision in the skin.
Bouncing flies cause us to beat ourselves around the head trying to catch them which is frustrating and maddening, but thankfully their hunting style can also be used as a means of control.
There are several varieties of hand held bug zappers which look like a tennis racquet and deliver a satisfying snap when they contact and incinerate a hungry fly.
However the best solution for hands free control is the use of adhesives. Deerfly patches is a commercial product which is affixed to a hat. They look like a large band-aid coated with a sticky flypaper substance.
For the do it yourself enthusiast who is not afraid of ridicule the ultimate solution is a variation of the patch adhesive solution.
There is an agricultural product called tanglefoot which is extremely sticky. It is used commercially to trap crawling insects and other pests. This can be spread with a spatula over a hard hat or novelty party hat to form an very efficient trapping surface. The hat will stick to anything after it is treated which includes children, pets, walls and fabric. It must placed in a safe location after being treated.
At the end of the season the hat can be discarded or scraped of dead insects and cleaned with WD-40.