Slide the 3/32" Black Bead to the eye of the Togens 2XL Curved Nymph. Wrap 0.01 Lead Wire along nearly the whole shank, then back over itself at the front for a taper; bind it with Black 8/0 thread behind and in front to level it off — the weight is the most important part of this fly.
At the bend, pinch a small bunch of Black Hackle Fibres and bind in a short, stubby tail.
Tie in the 0.2mm Black Brassie Wire at the bend and squeeze the tie-in flat with smooth pliers so it sits flat behind the lead. Throw a half hitch.
Dub Black Krystal Dub thinly and wrap a slender abdomen to about the halfway point; snip off anything sticking out — this is an underbody, keep it slim.
Rib forward with the wire in nearly touching turns so only a little dubbing pokes through between them. Secure, and cut the wire in the corner of your scissors to save the points.
Tie in a strip of Black 1/8" Stonefly Scud Back at the front of the abdomen, pointing rearward.
Dub a thorax of the same Black Krystal Dub up to the bead.
Pull the scud back over the thorax with only gentle stretch, bind it at the bead, fold it back over itself and bind again, then trim.
Tie off behind the bead. Pick out the thorax dubbing on both sides and underneath with a small dubbing picker for legs, and trim the underside so the legs come off the sides rather than the bottom.