I looked at the web(as I am sure you did) what I found is that they are attracted to flowers and plants with smell, if I were having this problem I would wash my clothing two or three times in fragrance free,(not unscented) cloths detergent. I would then dry them on the line as fabric softener sheet smell is in the dryer and it takes weeks to get rid of it. (my wife gets migraines from perfumes especially the fabric softener sheets) I would wear drab colors so I didn't look like a flower, I would use fragrance free deodorant, shampoo and anything else that might cause them to assume I was a flower. I would stay away from anything scented, candles, air freshener, little trees hanging in cars. I would make sure not to use citronella or paritherine as they are both plant products and may be an attractant. When I arrived the first day I would rub garlic on something I could take off like a cheap cotton glove and see if they were attracted by it or repelled by it, when I had it on. i would also kill 10 or 15 of the flies and rub it on something else and see if that repelled them. If the garlic worked I would rub it on my fishing vest and start eating it like crazy next year two weeks before I went fishing, If the dead bugs worked I would gather as many of them as I could and I would put them in an old blender with a cup or so of alcohol, i would then blend them up put then through a coffee filter and use the liquid to spray down my clothing as often as I needed to keep them off.
Sorry I have not experience with these particular insects just a little biology to work from.
I found a great site which explains how repellents work. http://www.madehow.com/Volume-3/Mosquito-Repellent.html I can understand why the don't work on the flies, as the flies aren't trying to bite they aren't actively landing on you because your a red blooded animal, its more your a convenient rest stop. with the perfumes etc they ad as masking fragrance to the deet etc. the repellents might be more of an attractant than a repellent.
Hope this helps
Eric
Last edited by Eric-WD; 05-07-2011 at 01:12 AM.
Reason: spell check
"Complexity is easy; Simplicity is difficult."
Georgy Shragin
Designer of ppsh41 sub machine gun