If you get a bite or sting make a positive identification of the insect or arachnid from which you received it. Not all alleged black fly bites are really from black flies. Get positive professional identification.
www.mainenature.org/blackfly/blackflyinfo.html www.mainenature.org/blackfly/blackflyinfo.html
Black Fly bites; Black fly bites (biting flies) can produce a number of symptoms including pain on and around the bite site, itching and cellulitis as reaction to bites progress. The most common allergic responses are hives or wheezing.
www.biteremedy.com/ www.biteremedy.com/
"Generally black fly bites cause some itching and minor swelling from the first few bites of the season, following which an immunity develops, with subsequent reduced reactions.  Nonetheless, even individuals who have lived all their lives in black fly country and are exposed every season, can have greater effects if...
www.thriftyfun.com/tf598029.tip.html
Black flies often occur in enormous numbers in the spring and early summer months, especially in the northern latitudes. Bites can be extremely painful, and their mouthparts are somewhat similar to those of a horse fly (bladelike and piercing) in the female.
ohioline.osu.edu/hyg-fact/2000/2167.html
Proper clothing offers good protection against black fly bites. Keep shirt sleeves and front closely fastened and tuck trousers inside socks or high boots. Zippered front shirts will keep flies out better than button shirts.
www.ultimate.com/washington/wla/blackfly/ www.ultimate.com/washington/wla/blackfly/
Black flies are small (1-3 mm), usually dark colored, biting flies with a distinctive "humpbacked" profile (right). Immature, or larval, black flies develop in fast flowing streams, rivers and creeks where they cling to the unders...
http://www.livingwithbugs.com/black_fly.html
Severe complications (swelling) from black fly bites are possible in allergic individuals and rare cases of death from toxemia or anaphylactic shock have been reported. In the United States, black flies are not known to transmit diseases to humans.
www.ipm.iastate.edu/ipm/iiin/blackfl.html www.ipm.iastate.edu/ipm/iiin/blackfl.html
In response to these chemicals, the area around bites swell, become painful and itchy. Black flies do not transmit any diseases to humans, but some people ... Black Flies don't like wind and are only active during the day. They prefer shade. They breed in fast flowing rivers so avoid climbing near these in Black Fly season.
www3.sympatico.ca/bob.bennell/black.htm www3.sympatico.ca/bob.bennell/black.htm
Not only can black fly bites be painful, itchy, and cause a strange numbness, but they can also transmit bloodborne pathogens. It's not exceptionally common for a human to contract a disease from a black fly, but because black flies do feed on blood, the possibility cannot be ruled out.
www.getridofthings.com/get-rid-of-black-flies.htm www.getridofthings.com/get-rid-of-black-flies.htm
The experience of being continually bitten, unable to step outside from countless bites, is a demoralizer with few equals, and if the flies are not deterred with repellents or controlled by insecticides they can badly disrupt any commercial or recreational outdoor pursuit in black fly areas.
www.lawestvector.org/black_flies.htm www.lawestvector.org/black_flies.htm