Hook TMC 200R (or TMC 2488 in the smallest sizes), 22 and larger on a straight nymph hook; use a curved emerger hook in size 24 and smaller
Thread Gray (or brown/black to match the hatch) 14/0 (or 8/0 for larger sizes)
Materials
Fine dry-fly/synthetic dubbing Gray superfine dubbing (Sparse pinch)
Antron or CDC wing fibers Gray cdc or antron (Small tuft)
How to tie it
Secure the hook and start the thread behind the eye; wind rearward in close touching turns down the entire shank to a point above the barb, forming a smooth, thin thread underbody (this pattern has no tail).
Apply a very sparse noodle of fine gray dubbing and wind it forward over the rear two-thirds of the shank, keeping the abdomen thin so it shows a lightly segmented look.
Tie in a small, sparse tuft of gray Antron/CDC fibers at the thorax as an emerger wing, roughly half a shank length long.
Dub a slightly fuller thorax with two or three turns of dubbing behind and in front of the wing.
Whip finish behind the eye and add a tiny drop of head cement.