Wrap .025 Lead Wire over most of the shank, leaving a little room at the back and front. At the front, wrap the lead back over itself to build a thick thorax; stoneflies have a big thorax compared to the rest of the body.
Start the Tan UTC 70 thread, wrap through the lead a few times, and build thread dams at the front and back so the lead cannot slide.
Take the thread to the rear and dub a small round ball of Golden Stone SLF Dubbing at the back end of the shank. This is the wedge for the tails.
Bind a Tan Goose Biot on each side with the natural curve splaying away from the body, about a quarter of the body length. Run the thread back to the dubbing ball to split them, then forward, and trim the butts.
Bind the D-Rib along the side of the fly, stretching it as you wrap back to the tail, and let it hang.
Form a dubbing loop with the SLF, staggered thin at the top to thick at the bottom to build the taper, spin it and wrap forward; make a second loop if needed. Keep it shaggy and stop just short of the thorax.
Wrap the D-Rib forward to the same point to segment the body and bind the dubbing down.
Snip three sections of Mottled Turkey Wing from small to large, treat them with brush-on Zap-A-Gap (or flexible head cement), and snip a V notch in each. Bind the smallest centered on top, extending back over the body, bite down with thread, and trim.
Dub a segment onto the thread conventionally, thicker than the body, and bind in the second wing case slightly overlapping the first without covering it; repeat with the largest, planning the spacing so room remains at the front.
Bind a Tan Goose Biot on each side at the front, splayed away from the hook as the last wing case did, for the antennae.
Dub the thread very sparsely, just enough to cover it, wrap to the front to build a small head, and whip finish (under the biots if you want them to stand up).
Brush out the underside of the thorax only for a leggy look; trim any long fibers near the back, which should stay less shaggy.