John Barr's BWO emerger, designed in the 1970s and a tailwater staple ever since. A drab, flush-riding pattern: stiff brown hackle fibers imitate the trailing shuck, a slim olive-brown abdomen suggests the nymph, and a dark dun wing case pulled over the thorax — its leftover tips swept back as legs — captures the dun struggling free of the shuck.
1. Thread base — Attach gray 8/0 thread and lay a base back to the bend.
2. Shuck — Tie in a small bunch of stiff brown hackle fibers at the bend, about one hook-gap long.
3. Abdomen — Dub a slim, tapered olive-brown abdomen over the rear two-thirds of the shank.
4. Wing case — Tie in a clump of dark dun hackle fibers at the two-thirds point, tips pointing forward over the eye.
5. Thorax — Dub a slightly fuller gray thorax (muskrat or beaver) up to just behind the eye.
6. Wing case + legs — Pull the dun fibers over the top of the thorax and tie down. Divide the leftover tips and sweep half back along each side as legs.
7. Finish — Build a small head, whip finish, and cement.
