Hook 2XL hopper/terrestrial, straight or curved, 8 (tie 4-10)
Thread Black 70 denier
Materials
Red squirrel tail Natural red-brown hair (Two small stacked clumps, one per claw)
Turkey or goose quill slip Brown veevus body quill (One slip for the shellback)
Hackle Brown to medium ginger hackle (One feather, palmered for the legs)
Chenille or yarn, small Brown ultra fine chenille (One length for the body)
How to tie it
Lay a base of black thread from behind the eye all the way to the bend. Note that on this fly the bend end is the crayfish's tail and the eye end is its head, so the claws go on at the bend.
Stack a small clump of red squirrel tail, measure it at least a body length, and tie it in on the far side of the shank at the bend with tight wraps, then lock the butts down with loose wraps forward and tighter wraps back.
Take a few thread wraps around the base of that clump only, as if posting a parachute, so the claw stays bunched and cocked out to the side.
Repeat with a second matched clump on the near side of the shank, starting it slightly toward you so it spins into position, and post it the same way; check that the two claws are even.
Tie in the brown turkey slip at the bend for the shellback, pointing rearward for now, and bury the excess.
Tie the hackle in by the tip a short way up the shank, not all the way back at the claws, so the legs will not run right up to the head end.
Tie in the brown chenille and wrap the thread up to where the body will finish; make one thick wrap of chenille behind the hackle tie-in, then wrap forward turn against turn to build the body and tie it off.
Palmer the hackle forward over the body in open spirals, tie it off with two or three wraps and snip.
Push the hackle fibres out to the sides, then draw the turkey slip forward over the top of the body, take a couple of loose wraps to check the position, then lock it in and trim.
Smooth out a small head, whip finish and add head cement.