Our friend from across the pond, Andy Baird, is bringing the small fly challenge to us again. Check out this wonderful little size 24 Generic Spinner he recently posted on his blog, Small Fly Funk. How small is that? The hook shank is less than 1/4 inch long.
Click on the link above, and there's also a neat step-by-step of Andy tying a size 20 quill body dun. The lack of bulk combined with natural symmetry give his flies a very natural aesthetic few tyers can match when tying such diminutive patterns. Great work, Andy.