You can get some of these jars and fill them with a couple of inches of cider vinegar. The flies come up through the hole in the bottom and can't find their way out. I have one of these in my yard and it catches flies and gnats. I sure wish that it would catch mosquitos too. I don't know if it would attract the black flies or not.
http://cgi.ebay.com/Vintage-Thin-Gla...3A2%7C294%3A50
I've heard that putting fabric softner sheets in your pockets repels mosquitos. I'm going to have to try this one again and see if it works.