An old farmer

An old farmer was hauling a load of manure when he was stopped by a state trooper. "You were speeding," the cop said. "I'm going to have to give you a ticket." "Yep," the farmer said as he watched the trooper shoo away several flies. "These flies are terrible," the trooper complained. "Yep," the farmer said. "Those are circle flies." "What's a circle fly?" "Them flies that circle a horse's ass," answered the farmer. "Them are circle flies." "You wouldn't be calling me a horse's ass, would you?" The trooper angrily asked. "Nope, I didn't," the farmer replied. "But you just can't fool them flies.