Main's streams are cleaner. You can tell by the black fly bites.Black flies are known (and hated) for their vicious bites, but the little buggers are also sticklers for cleanliness. They like to lay their eggs in pure water. For a time in Maine, that was a problem. Paper mills and other industries fouled Maine's streams and that held down the black fly population. But, the Boston Globe reports, as the state's waterways have grown cleaner over the years, the black fly population has buzzed.Now they are "so thick you breath them in and they get stuck in your throat. They even get under your eyelids," said one Mainer. Other states work to control the black fly by treating streams with a bacteria that kills the critter's larvae. Maine officials say they have worked hard to get their rivers clean and don't think it's a good idea now to fuss with them. Besides, trout love munching the flies.