Booty's Better Emergers feature a foam thorax and abdomen, which allows for superior bouyancy on high gradient trout stream.  These Quigley-style imitations for mahogany duns, pale morning duns, and blue-winged olives are killer!  Available from Snake River Angler (www.snakeriverangler.com) and Montana Fly Company (www.montanafly.com) in sizes #12 to #20.