Lay a Brown thread base all the way back to the start of the bend.
Tie in two fibers of dark moose body hair as the tail; they split naturally, or lift them and put a wrap underneath. Trim the butts and bury them under thread.
Catch in the Brown palmered hackle at the rear, binding it all the way back to where the palmering starts, and bury the stem.
Wax the thread and spin a fairly tight noodle of Hare's mask fur (underfur from the cheek plus some guard hairs from above the eye). Take it back to the bend and dub forward in evenly spaced wraps, stopping right under the eye. It will be buggy; that is the intent.
Palmer the hackle forward in evenly spaced turns, then take a few close turns at the front for more of a front hackle. Catch it off with two wraps and snip as close as you can.
Take the thread back to the wing tie-in point and add a little more thread base so there is no step.
Stack a clump of Deer body hair about the size you would use for an elk hair caddis, measure it a little past the bend (it will flare and shorten), and tie it in with a pinch wrap pulled tight on the near side. Add another wrap, check it has not spun, then lift the hair, take a wrap or two underneath and two locking wraps on top.
Cut the butts off as close as you can get them; this is not a bullet head. Push the stubs up with a fingernail and build a small head straight behind the eye, keeping the eye clear.
Whip finish with three or four turns, add a small drop of head cement and spin the fly to even it out.