Put seven or eight wraps of 0.020 lead-free wire near the back of the hook, then build a tapered underbody over it with black Uni-Stretch and whip finish. The wire under the rear does two things: it sinks the fly and it gives you the fat back end that a sedge pupa has. Uni-Stretch builds that taper far faster than thread.
Attach dark brown 70 denier thread, tie in medium gold wire for the rib and continue smoothing the taper over the Uni-Stretch.
Dub a fairly thin noodle of dark green olive peacock dubbing and wrap it over the built-up body, covering about two thirds of the shank and leaving room at the front. Because the underbody is already shaped, the dubbing only has to cover it.
Counter wrap the gold wire forward for even segmentation, tie it off and helicopter the tag out.
Smooth the head area out with thread, because the smoother it is the easier the peacock herl goes on.
Tie four or five pheasant tail fibres in on each side for legs, about the length of the body, and cover the butts.
Wrap one or two strands of peacock herl for the head, tie off by pulling down on the thread to snap the herl clean, whip finish and add a dab of superglue to the wraps.