Mount a #12 1XL dry fly hook with fine black thread (12/0), lay a small base and leave the thread hanging about a quarter to a third back from the eye.
Take a clump of White calf tail at least twice what you need. Grip it near the tips and pull the short hairs out, repeat a couple of times to thin it by half, pull out the extra-long ones, then stack it in your fattest stacker; crinkly calf needs a lot of stacking.
Measure the wing one shank-length long, take two soft wraps keeping it on top, then six or seven progressively tighter wraps working back. Lift the butts at 45 degrees, slide the scissors in parallel to the shank and snip for a taper; bind the butts down.
Take the thread to the bend and tie in a fair-sized stacked clump of natural Deer hair as a tail one hook-gap long: three securing wraps, then medium wraps working back so it doesn't flare.
Bring the thread forward, gather all the deer hair butts and cut them at 45 degrees parallel to the shank so they bind into a flat, uniform underbody.
Work the thread back to the wing, come underneath, lift the calf tail upright and build a thread dam in front to prop it. Split the bunch evenly with bodkin or fingers and set the two wings with three figure-8s; two or three turns around each base if you want a post look. Snip any wild fibers now.
Catch in three fine strands of Peacock herl at the bend (the brittle tips snipped off), advance the thread to the end of the rear segment, give the strands a light twist into a rope and take three or four wraps. Catch off and cut.
Catch in yellow floss, pull it taut, and with the thread left forward wrap the floss back and forward over the middle of the body, twice if you want a fatter band; secure with a couple of wraps.
Catch in the same herl ahead of the floss, twist and take about three wraps for the front segment, backing the first turn slightly if the floss band is too wide; secure with two wraps and snip.
Take two Brown rooster dry fly hackles with a good length of bare stem stripped, catch them in behind the wing leaving a little bare stem to start the wrap, secure the stems forward and snip. Wrap both together, three turns behind the wing and three in front; two securing wraps.
Grab all the forward-pointing fibers in your fingers and snip them close, pinch the rest back and flatten the head area, then whip finish.