Dub a slightly buggy body of rusty amber translucent dubbing over the rear three-quarters of the shank.
Clean the underfur from a bunch of elk hair, stack the tips, and tie it in at the front with the tips pointing forward over the eye. Measure so that when it later folds back, the tips extending past the rear tie-down give you the tail. Bind the butts firmly, leaning on the thread.
Tie in a brown saddle hackle at the front and take four or five turns at the head for the legs.
Palmer the hackle back over the body in even open turns, bringing the thread back together with it; secure at the bend and trim.
Trim the hackle off the top of the body so the shellback can seat tight, and trim the body hackle short. Leave the front leg turns full.
Pull the elk hair tight back over the top as the tied-down shellback and bind it at the bend, leaving the tips as the tail.
Whip finish at the rear tie-down and cement.
For slick water, also trim the bottom hackle flat so the fly sits down in the film with just the side legs kicking out.