Here's a step by step for the Isonychia Nymph I tied for the Nymph Swap Fall 2010 as requested by a few folks. It's a lot easier to tie than it looks from the number of steps, and it's a deadly pattern in late spring/early summer and again in the fall (Isonychia hatch 2x a year on many streams in the east).
It's a dark slender nymph, often with a prominent white dorsal stripe, and it's a very active swimmer, so a retrieve with short strips can be effective.
Recipe in order of tie in
Hook: 3 xlong size 10 or 12
Weight: Non toxic lead wire substitute about same thickness as hook shank, (.015" here)
Thread: claret or wine colored thread preferred (brown or black is also fine)
Tail: 3 Peacock Sword fibers
Dorsal stripe: white thread (Danville's flat waxed nylon here), floss or stripped hackle stem
Back of nymph: Turkey tail fibers
Gills: 2 gray ostrich herls, tied 1 along each side of shank
Ribbing wire: fine gold, copper or claret wire
Abdomen and thorax: Coarse dark brown dubbing
Legs: Brown grouse, partridge or hen feather
From left to right:
Coarse Dark Brown dubbing (rabbit, Haretron etc)
Claret or wine 8/0 thread
Turkey Tail feather for back of nymph
Fine wire for ribbing copper, gold or claret
Partridge feather for legs
Non toxic .015" diameter wire for weight
Size 10 or 12 3xlong nymph hooks
White dorsal stripe (white Danvilles' Flat Waxed Nylon thread, floss or hackle stem)
Peacock sword for tail
Gray dyed ostrich plume for lateral gills:
Step #1: Mount Thread
Step #2 Weight Shank:
Step #3: Tie in 3 Peacock sword fibers for tail:
Step #4: Tie in thick white thread, floss or stripped white hackle stem for the dorsal stripe (a prominent feature on many Isonychia nymphs)
Step #5: Tie in a strip of turkey tail fibers for the back of the nymph
Step #6: Tie in the ribbing wire:
Step #7: Tie in ostrich herl along each side, these will become gills
Step #8: Apply dubbing to thread
Step #9: Dub abdomen
Step# 10: Pull ostrich herl along each side of abdomen and tie off to form gills.
Step #11:Pull turkey slip over back of abdomen and tie down
Step #12: Pull over dorsal stripe and tie down
Step #13: Counter rib abdomen and tie off
Step #14: Fold back excess strip of turkey fibers and dorsal stripe to form thorax.
Step #15: Tie in a brown partridge or hen feather on top of shank by its tip, dull side of feather facing up. This will be pulled forward over dubbed abdomen to form legs.
Step#16: Apply thicker amount of dubbing to thread to form thorax
Step #17: Dub thorax and pull partridge feather over top and tie off to form legs.
Step #18: Pull turkey fibers then dorsal stripe over top of thorax and tie off