Trailing shuck Amber Zelon or wood duck (small tuft)
Dubbing Mahogany/dark brown (as needed)
Dorsal stripe (optional) White floss (1 strand)
Emerger wing Dun CDC or Zelon (1 tuft)
Hackle Brown or grizzly hackle (1 feather)
How to tie it
Start thread at the bend of a curved hook. Tie in a short amber Zelon or wood-duck trailing shuck, half a shank long.
Dub a slim mahogany body up the curve to the thorax; for the Iso marker, lay a strand of white floss along the top first and pull it over as a dorsal stripe.
At the thorax tie in a short CDC or Zelon wing tuft angled forward, the emerging wing breaking the film.
Dub a slightly fuller thorax.
Wind 2-3 turns of brown or grizzly hackle at the thorax, then trim the fibers flat underneath so the fly sits low in the film.