please HELP !!!

Does anyone out there have a good remedy to keep black flies from biting dogs? Those little *&%$# things are really bad right now and they are eating our little girl alive! She is wearing a citronella collar but it does no good at all. We just spent 10 minutes squishing probably 100 which were burrowed deep into her fur and biting her delicate belly and armpits. Now, she's blonde and they're black and I couldn't see them until I ran my fingers through her fur and clouds of them came out. I pinched them dead as fast as I could and each one was full of her blood. When we were sure we had them all we looked up and both windows in the room were suddenly covered with the ones that flew off her and escaped. They met their end with a good dousing of OFF. But we can't put that stuff on her. So, what do we do?

I called the vet in Burns Lake, who I'm happy with for the most part. I'm confident in the doctors and the assistant is good, but she tends to never really have time to talk for a minute. I always feel like I'm getting the bum's rush when I call there. I can appreciate that they are probably very busy, but this is my suffering puppy we're talking about and I want a little sympathy. Anyways, she wasn't really any help. So, I guess my next step is Google. Whatever did we do before Google?