I just though of a trick my wife, who has a lot less time camping than I do, taught me to take care of most flying critters while camping, be they black flies, snow flies, meat bees, or whatever. Come dinnertime, open a can of the cheapest cat food you could buy, and put it 20 ft or so away from your eating area. Those nasty flying critters will swarm the cat food, leaving you pretty much in peace...