Eyes (weight) Medium bead chain or small dumbbell (1 pair)
Head Epoxy or UV resin over the eyes, colored (1 coat)
Legs Olive or amber Sili Legs (2-3 pairs)
Wing/tail Olive deer hair or bucktail, tips splayed (10-20 hairs)
Collar Olive Z-lon or Antron (1 sparse clump)
How to tie it
Lash bead-chain or small dumbbell eyes across the shank at the 30% mark, behind the hook eye.
Tie in 2-3 pairs of Sili Legs at the eyes with figure-eights so they splay out to the sides.
Tie in a small bunch of olive deer hair (10-20 hairs) behind the eyes, tips extending a shank length past the bend and flared. The flare is the 'legs kicking' trigger of every Bitters-style fly.
Add a sparse Z-lon collar over the deer hair butts.
Coat the head area, eyes, and thread wraps with tinted epoxy or UV resin, shaping a smooth wedge head. This makes the fly nearly indestructible and gives it its glassy crab-like carapace.
Whip finish behind the head before the resin cures and trim legs to length.