Hi Deanna!
Yes, Ultrathon is what I started with. No effect whatsoever. I even went so far as to use 100% deet, to the point that the smell was making me woozy. Didn't work.
As Eric stated, they don't bite - it's just the psycholigical reaction to having flies crawling on your skin. Hence my solution - no exposed skin. I have a "bug suit" that I use for early archery season. It's a soft type of mesh that allows air to circulate, but bugs can't touch you. It'll make lighting my pipe an adventure!
H.A.
Here's a shot of Croatalus - notice his "friends".