I believe bow hair bugs are not actually mites, but the larvae of the carpet beetle, a critter that eats natural fibers of all kind..wool, horse hair, and other stuff.

http://www.getridofthings.com/get-rid-of-carpet-beetles.htm

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7436.html

http://www.talkbass.com/forum/archive/index.php/t-352415.html

http://www.johnsonstring.com/Bitten%20By%20Bug.htm

http://ezinearticles.com/?Whats-Eating-Your-Violin-Bow-Hair?--It-Might-Be-Bow-Bugs&id=2461787