Those little buggers are called noseeums. Probably because they are so small, you no see um
They are the worst biting insects I have ever encountered. Several places in Utah are miserable with them (usually high desert areas). They are THICK in the area you are hunting for some reason.
They prefer to bite along the hair line, ears, crawl around in your hair and bite your scalp (anywhere that is sweaty, so don't drop your pants). The day after is the worst. They welt up and turn bright read around the bite and itch like a mother. Most repellents don't even bother them, but do seem to attract them. The 100% deet is king and the only thing that seems to work. It is hard on humans and your gear. I don't know how the sheep and antelope handle them biting them constantly. They drive me into insanity. I have left the same day I have arrived on several trips in that country. I just couldn't stand them. Flinch