Dan... Although I guess the skeeters are horrendous in some areas of Alaska in the summer, I may have been bitten by ONE mosquito in my five trips to Alaska during September...
However, as the previous posters have said, the whitesox and some other small black-fly like critters ( I call moose-pecker flies) can make your life miserable on calm or warm days...They ESPECIALLY like to chew on your hands as soon as you get some blood on them...On some trips my hands were so swollen after butchering and caping animals that you could not even see my knuckles.. From this I learned to take latex gloves to wear while butchering or caping..They keep your hands clean and keep the bugs from biting them also...
Take a headnet... After my first trip or two I said that I could get by with lots of 100% DEET, but on my last hunt I really wished I had a headnet...A couple of times when the wind died down and the sun came out the bloodsucking little bastards swarmed my face big time... You may not need it, but it's light, doesn't weigh much and can save you a lot of discomfort..