The long and short of it is that you want to avoid being bitten by these insects. But insect repellents won’t stop all of the flies when it’s time for them to get a meal.  For that, you need to wear protective clothing.  And you can even choose clothing that makes you look less delicious to a fly!

For some reason, Black Flies and Deer Flies prefer shiny, dark things to light colored things.  So start off by wearing light colored clothing, including a hat.  If that’s not enough, you can do even more to keep from being bitten.  There are fly patches that you can affix to the top of a baseball cap.  They’re made of a sticky material, so when the fly lands on it to feed, it’s stuck like flypaper.  Or for the best protection, a hat with netting can’t be beat.