Thread White (GSP), or to match body 50 denier GSP (or 8/0)
Materials
Hackle fibers (tail)
Antron or Zelon (post, optional) White poly yarn
Dry-fly dubbing (body) Yellow (sulfur)
Dry-fly hackle Barred ginger, cream, or white dry fly hackle
How to tie it
Start the thread on the shank (GSP is slippery, so take several wraps to catch it).
Tie in about ten fibers from your hackle as a tail, roughly one to one-and-a-half body lengths long; snip the excess so it won't interfere with the post.
Optional post: tie in a small clump of white Antron/Zelon upright and take a few wraps around its base to stand it up (not a full parachute post, just for visibility); trim it a little shorter than the finished hackle height.
Wax the thread, dub a thin yellow noodle, and wrap a slim tapered body forward.
Tie in a barred-ginger (or cream/white) dry hackle and wind a few turns, about two wraps behind the post and two or three in front, keeping clear of the eye.
Tie off the hackle, sweep the fibers back, and take a four-turn whip finish; trim.