they don't seem to be fine enough for the no see ums. In fact we have never seen the no see ums. They seem to have gotten in the boat on Spanish Cay, maybe because we went for a hike there on the beach. Then in Rock Sound a different bug (also unseen) raising a different looking welt appeared. Have had minor problems elsewhere. After trying numerous drug store and home remedies, the most effective has been to heat the bite with hot water, a hot spoon, or a hair dryer as hot as you can stand for as long as you can stand (20-30 seconds), which seems to relieve the itch for several hours. I have has perhaps 10 bites, Ann more than a hundred I would guess - so they definitely have a preference. The two times that Ann was attacked the worst, she had tried Skin-So-Soft, and often prescribed repellent. Our conclusion was that these particular bugs are attracted to it. She is now wearing the 30% DEET stuff on trips ashore, I continue to wear nothing at all

We have some really excellent but proof shirts, purchase in anticipation of the black flies in Georgian Bay which were never encountered. But I haven't resorted to them yet.