Start the black thread at mid-shank; the whole fly is built at the middle of the hook.
Cut the 3mm red foam into a rounded piece and catch it in on top at mid-shank with a pinch wrap. Take several more wraps before letting go, flatten the tie-down area, and leave the thread at the middle of the foam.
Fold a 3-inch piece of white rubber in half and set it on top with two or three loose wraps. Work a leg off each side, then build a small band of loose wraps between them, tightening progressively so they cannot spin.
Prepare a grizzly dry-fly hackle with barbs about one and a half hook gaps. Bind the bare stem in ahead of the legs, almost up to the eye, and snip the excess.
Take two turns of hackle in the middle between the legs, then lift the front of the foam and take four or five turns in front. This is a heavily hackled fly.
Tie off and snip the hackle, sweep back any barbs going forward, and take just enough wraps for a small head with room for the whip finish.
Whip finish, then cut the leg loops open and trim all four legs short.