Aaugh! Whiteflies?

Little whitish/grayish mothlike creatures are flitting about everywhere, literally overnight, as I understand whiteflies are wont to do. But I've been reading that whiteflies are much smaller than these guys, who are about a third of an inch long. Any guesses as to what I might be dealing with? I don't have much growing in my fall garden, but what I do have is doing quite well, and I would hate to lose it to some little sapsuckers! Will try to get pictures but they move really fast and don't sit still for long...