Hackle Brown and grizzly hackle (clipped on bottom)
Head Spun deer hair (clipped)
How to tie it
Mount the 2x long hook, lay a thread base.
Tie in a short red tail at the bend, a tag of deer hair or hackle fibers, about a quarter shank length.
Build a robust yellow body with dubbing or yarn to the 60% mark. Some tyers loop the yarn back over itself at the bend for a plump abdomen.
Lacquer a turkey quill segment ahead of time so it won't split. Fold it and tie it in as a tent-wing over the body, extending just past the bend.
Tie in a knotted hackle-stem leg on each side, knots pointing up and back like bent knees. This is the detail that sells the fly. Position them carefully.
Wrap brown and grizzly hackle at the collar, then clip it flat on the bottom so the fly sits low.
Spin and pack deer hair for the head, then trim it square-ish with a flat face. Whitlock's collar-and-head is the hardest step; leave a few natural tips sweeping back.
Whip finish, cement.
Substitutions
Body instead of Yellow dubbing or yarn: Yellow foam strip — More buoyant, modern approach; Tan dubbing — Subtler, natural grasshopper color
Wing instead of Turkey quill segment: Mottled Thin Skin — Way more durable than turkey quill; Medallion sheeting — Pre-printed, realistic; Elk hair — Simpler, more buoyant. Makes it more like a Stimulator
Legs instead of Yellow grizzly hackle stems: Round rubber legs (barred yellow) — More movement, easier to tie in; Knotted pheasant tail fibers — More realistic jointed legs; Sili Legs (barred) — Great movement in water