Catch the thread on a little behind the eye and leave a long tag end; this tag becomes the rib. Wrap back a short way and hold the tag in the material clip out of the way.
Tie in the fluorescent yellow Antron yarn on top with a pinch loop, a couple of turns to secure, a few more wraps, then snip the waste. Carry the thread down to the bend.
Strip a few fibers from the badger saddle and tie the hackle in by the stem, leaving a short length of bare stem showing behind the tie-in so the first turn of hackle seats without trapping.
Catch in a couple of strands of peacock herl at the bend, then take the thread back up the shank to the post and take a few turns in front of it to stand it at 90 degrees.
Wrap the peacock herl forward in touching turns to the post, hold the post back and continue in front of it, secure with a couple of turns and trim.
Palmer the badger saddle forward in slightly open turns, with one turn in front of the post, tie off and trim; brush the fibers back and take a few turns to secure.
Wiggle the thread tag forward through the hackle as a rib, trapping as few fibers as you can, secure with a few turns and snip it.
Sweep everything back, neaten the head, and do a three-turn whip finish so the head stays light. Snip the thread.
Trim the Antron post to the length of the hackle fibers and stroke the fibers forward.