Lay a base of brown thread down to the start of the bend.
Separate two Pheasant tail fibers, roll them apart in your fingers if they are stuck together, and catch them in on top as a tail about one hook length long. Spread them apart; a drop of super glue or UV resin at the split keeps them separated through the tie.
Catch in the Brown D-rib up front with the round side toward the hook, and bind it back along the shank parallel to the hook to build underbody bulk.
Wax the thread well and dub the Amber seal's fur (or sub) on as tightly as you can, spinning it tighter after the first couple of wraps. Dub forward to the front, then back down and up again to build a taper: thinner at the rear, thicker at the thorax.
Spiral the D-rib forward in three or four turns so the round face shows, catch it off with two or three tight turns, and snip.
Lay the first Jungle cock eye flat on top of the thorax, reaching about halfway down the body. Catch it in with a couple of loose wraps, check it is lying flat, then lock it with a couple more and snip the stem.
Wax the thread and dub a little more Amber seal's fur ahead of the first eye to give the two wingcase pieces some separation.
Lay the second Jungle cock eye on top, slightly forward of the first, and hold it tight while taking two firm wraps so it does not spin around; snip the stem.
Catch in a Partridge feather and take one or two turns as a collar. Snip the butt, bunch any fibers that ended up on top and push them down beneath as legs with a couple more wraps.
Build a good-sized nymph head, trim off a few fibers on top so the legs come off the sides and bottom and the wingcase shows, whip finish, and add a drop of head cement. Trim any long stray dubbing fibers.