Here is the recipe. Hook: size 12 or 14 dry fly hook. Thread: Iron gray 8/0 (could be black or gray/dun). Tails: 5-6 barbs of dun hackle (could use microfibetts). Wing post: barred flank feather from a male pintail (could use mallard flank). Abdomen: gray turkey biot. Thorax: Adams gray superfine dubbing. Hackle: dun saddle or neck hackle.
The fly is pretty easy to tie once you've mastered the art of hackling a parachute. The triploids at Leech Lake love this fly; I've watched cruising trout stop, orient toward the surface, and then crash the fly (www.washingtonflyfishing.com/gallery/showphoto.php?photo=13443&ppuser=3541). It is not the most durable fly as trout teeth can rip the biot body, but with its thin thread abdomen, trout have taken it even if I've had to trim out the remains of the biot.
I also tie a spinner version with two spread tails, the same biot abdomen and thorax, and a conventionally tied dun hackle which I trim flat top and bottom. The hackle represents the spread wings of the sprinner and therefore, no other wing is required.