Lay a base of 12/0 black thread down to the start of the bend on a size 12 standard-length dry fly hook.
Tail: bind in a very small clump of Grizzly hackle fibres, about ten, no more than a hook gap long. Set them a little further back than feels natural to lengthen the body, then bind the butts forward with loose wraps - that avoids a lump at the back and thickens the underbody slightly.
Body: strip the barbs off a leftover grizzly hackle to make a quill, and bind it in by its thin end.
Wrap the quill forward in touching turns, stopping short of the eye to leave room for the remaining components. It starts as a very fine rib at the back and thickens toward the front, which gives the striped, variegated look. Tie off. A drop of UV resin over it costs a little segmentation but makes it far more durable.
Thorax: tie in a strand of black ostrich herl and take three or four wraps, then tie off. Do not skip it - this is what props the wings and the throat up.
Wings: catch two small Grizzly hackle tips in on top with three wraps, then set their orientation and separate them slightly before adding securing wraps. Handle them gently, they are not strong. Snip the butt ends as close as you can.
Throat: even the tips of ten or twelve deer hairs by hand, turn the hook over and bind them under the shank reaching to about the hook point, with a pinch wrap and two more. Snip the butts off before turning the fly back over.
Take the thread up to the eye, build a small dry fly head, whip finish and add a drop of head cement.