Tail Coq de Leon, medium to dark pardo (dark dun hen in the original) (a healthy clump)
Rib UNI-French wire, small silver (one strand)
Body Delaware River Club dubbing, mahogany brown (sparse, dubbed tight)
Thorax Peacock herl (two strands)
Hackle Hen hackle, dark dun, dark brown or grizzly (one feather, three turns)
How to tie it
Mount an Allen N202 in size 12 (a hopper and terrestrial hook, but ideal here) and pinch the barb down.
Start black UNI 8/0 at about the halfway point and work back to the tail tie-in just in front of the barb.
Take a healthy clump of Coq de Leon in medium or dark pardo, keeping the tips together, and measure it so the tail runs about three-quarters of the way back from the eye. The original recipe calls for dark dun hen fibres; Coq de Leon is more resilient and will not tear.
Lock the tail in with a few wraps, check the length, then wrap back a little.
Tie in the small silver UNI-French wire rib so it extends up the shank. That tie-in gives the body a bit of width to build on.
Trim the tailing butts just behind the eye, then bind everything down smooth and return the thread to just in front of the barb.
Dub a very tight, fine noodle of mahogany brown DRC dubbing. This is a blend that reads purple on some days and light olive on others, which is much of why it works for the emerging Isonychia.
Wrap the body forward in touching wraps, checking no thread shows through, and going back over any thin patch. As you reach the eye, wrap back a little to build the thorax up.
Pull any long stray fibres out of the way, then bring the wire rib forward, take a few firm wraps in the thorax area and helicopter it off.
Tie in two peacock herls by their tips with one loose wrap, pull them by the butts to set them, and lock them down. Wrap the thread well back over the thorax first. You want plenty of clear space at the front for the soft hackle, and an extra wrap back costs nothing.
Advance the thread, wrap the peacock herl forward over the thorax and tie it off with five or six wraps near the eye.
Prepare the hen hackle by stripping the scruffy fibres off the base and removing all the fibres from one side of the stem, so there is a clean gap to tie in at. Tie it in at that gap.
Attach hackle pliers to the stem and take three turns, helping the feather unwind evenly and pushing against the grain so all the fibres sweep back after each turn.
Lock the hackle down, tidy any fibre that has gone astray, and finish with two whip finishes. No head cement is needed. Trim the thread away.