Tail/shuck Brown marabou tips or Z-lon (trailing shuck) (small bunch)
Abdomen Pheasant-tail fibers or PMD-dun dubbing (small bunch)
Rib Fine gold wire (1 length)
Wing Light elk or deer hair, forward over the eye (small bunch)
Thorax PMD/pale yellow-olive dubbing (1 pinch)
Hackle Grizzly or dun dry-fly hackle (1 feather)
How to tie it
Start thread and tie in a trailing shuck of brown marabou or Z-lon at the bend, about half a shank length, to imitate the nymphal skin the dun is stuck in.
Tie in fine gold wire, then wrap pheasant-tail fibers (or dub) forward to the 50% point to form a slim segmented abdomen and counter-rib the wire forward in 4-5 turns.
Tie in a clump of light elk hair as a forward wing with the tips extending over the hook eye, then trim the butts in line with where the thorax will be.
Tie in a dry-fly hackle at the base of the wing.
Dub a PMD-colored thorax around the wing base, then take three hackle wraps behind the wing and two in front and tie off.
Whip finish behind the eye; the fly should sit with its butt/shuck in the film and the wing cocked forward like a crippled emerging PMD.