Hook Umpqua XS506 60-degree jig hook, fished point up, 2
Thread Light olive 140 denier
Materials
Lead eyes Plain (Small (extra-small to medium depending on size and depth), one pair)
Lead wire n/a (.020, about 20 wraps on the shank)
Deer hair / rabbit fur blend (carapace) Natural and olive deer hair with olive variant rabbit, roughly 60/40 rabbit to deer (Several small stacked clumps)
Head cement Clear head cement (Over the eye and lead wraps)
How to tie it
Mount the size 2 jig hook with the point down to start. Lay a thread base of 140 denier light olive from the upright down to the hook eye, back up, then all the way to the bend and forward again to the upright.
Tie the small lead eyes in on the corner of the upright with X-wraps in both directions, building a swell of thread around them, then take wraps around the base of the eyes between the eyes and the shank to cinch the internal wraps tight. Check that everything is square with the hook.
Wrap about 20 tight turns of.020 lead wire on the shank just forward of the bend, break the ends off and cross-hatch thread over it to smooth the transition. Hang the thread at the bend.
Add head cement over the eyes and lead and let it dry. This fly is best stage-tied in batches.
Prepare the carapace material: cut natural and olive deer hair off the hide, cut olive variant rabbit off a magnum zonker strip, and blend the two like dubbing (in a bag with a can of air) at roughly 60% rabbit to 40% deer hair.
Turn the hook over in the vise so the point rides up.
Hand-stack a small tuft of the blend, lay it across the shank with its centre at the bend and take two turns to flare it in place. The deer hair and rabbit flare together. Slide it back out of the way.
Move the thread forward slightly and repeat with clump after clump, each centred just in front of the last, flaring the material only on the point side of the hook so the shell builds on the top of the fly and the underside stays clear. Keep the clumps small.
Work all the way up the shank to the lead eyes, then whip finish behind the eye.
Trim the flared bundle to the flat, rounded crab carapace shape.