Hook: Daiichi 1870 #14
Tail: Pheasant tail dyed black
Rib: Chartreuse ultrawire, brassie
Body: Pheasant tail dyed black
Wing case: Pheasant tail dyed black
Thorax: Peacock here dyed black
Legs: Pheasant tail dyed black
Thread: Danville 6/0 black
I first came across this pattern in John Gierach’s book Good Flies in which he recounts its invention by Ken Iwamasa and first published in his 1988 book Iwamasa Flies.
The original was designed as a copy of mayfly nymphs which would arch their abdomens when dislodged from the bottom. Today, there are many variants on the pattern tied because it looks so life like (to the angler at least, who knows what the trout thinks). Tied in a 2X heavy Daiichi 1870, it’s an effective pattern near weed beds on reservoirs, the inverted hook reducing snagging.