Hook Articulated shank (front) joined to a standard 2X-3X long nymph/streamer hook via wire/braid loop; adult stonefly foam pattern, Articulated: rear shank #4-8 + front hook (e.g. TMC 5262 or 5263) #6-10
Thread Orange (salmonfly) or yellow (golden stone) 6/0 (140D)
Bottom body foam 2mm foam, orange (salmonfly) / yellow (golden stone). 1/4" strip for salmonfly, 3/16" for golden (1 strip)
Top body/overbody foam 2mm foam, darker. Black or brown (tapered, V-notched at rear) (1 strip)
Body dubbing/segmentation Orange or golden stonefly-colored dubbing (e.g. Ice Dub / Antron) under the foam (pinch)
Rear legs Round rubber legs, barred (black/orange or black/yellow) (2-3 pair)
Front hook body foam 2mm foam matching the body, over dubbing (1 strip)
Front legs Round rubber legs, barred (2-3 pair)
Wing / indicator Poly yarn or EP fibers over the back, plus a hi-vis foam or poly indicator post (small tuft)
Connection Coated wire or Senyo's braid loop (1)
How to tie it
REAR SECTION: Place the articulated shank in the vise, eye vertical. Start thread just behind the shank eye and wrap back one shank length (about 1" for a salmonfly, 7/8" for a golden stone).
Wrap a pronounced bump of thread at the rear and tie in two goose biots as tails on top; the thread bump splays the biots into a wide V.
Cut a strip of 2mm foam (1/4" wide for salmonfly, 3/16" for golden), trim one end to a point, and tie the point to the BOTTOM of the shank at the tail base (this is the belly).
Taper the darker top foam strip to ~3/16" and cut a shallow V-notch in that end; tie it in on TOP of the shank over the tails so the V-notch flares up over the tail base.
Dub a thin body over the shank, then pull the bottom foam and top foam forward and bind them down at intervals to create 2-3 clearly segmented body sections. Add a pair of barred rubber legs at each segment junction, sweeping back.
Tie off, build the connection loop (coated wire or braid), and attach the FRONT hook.
FRONT SECTION: Start thread on the front hook. Repeat the foam-over-dubbing body for the thorax, adding a pair (or two) of barred rubber legs at the front.
Fold the top foam forward over the thorax to form a head/wingcase and tie off behind the eye.
Tie in a poly-yarn or EP-fiber wing swept back over the body, and set a hi-vis poly or foam indicator post on top so you can track the big fly.
Whip finish and cement. Trim all rubber legs to roughly one body-segment length.