Mount a curved Klinkhamer-style hook and start olive thread one third back from the eye.
Tie in a tall white poly post at that point, standing proud of the shank by one shank length, and build a firm thread base up the post — the parachute hackle needs something solid to wrap against.
Wrap the thread back and down around the bend.
Dub a slim olive body forward from deep in the bend up to the post. The body hanging below the surface is the whole design: the abdomen sits in the water and the post sits above it.
Tie in two strands of peacock herl and wrap a small thorax around the base of the post.
Tie in a dun hackle at the post and take 4-5 generous turns horizontally around the base, working downward, then secure it against the post.
Whip finish at the post rather than behind the eye and cement sparingly, keeping cement off the hackle.