Note: This recipe has not been verified against a documented source, or disagrees with one. Treat the materials and steps as unconfirmed.
Classic Recipe
Hook Standard midge, 20-24
Thread Black 8/0
Materials
Body Black thread (tapered)
Rib Fine silver wire (2 inches)
Wing White poly or CDC (tiny puff)
Thorax Black dubbing (small)
How to tie it
Mount hook, start thread at the bend.
Build a smooth, tapered body with thread wraps alone. Thin at the tail, slightly wider toward the thorax. The taper should be gradual; take your time and avoid lumps.
Tie in 2 inches of fine silver wire at the bend and counter-wrap forward in 5-6 evenly spaced turns. The silver rib over the black body creates the segmentation trout look for.
Dub a tiny thorax. Just 2-3 wraps of black dubbing, slightly wider than the thread body.
Tie in a tiny white wing puff at the head, 3-4 fibers of poly or CDC. This represents the emerging wings.
Whip finish with the smallest head you can manage.