A low-riding stonefly.

hook ? Dai Riki 280 #10
thread - UTC 140 olive
tail - deer hair dyed olive
body - tying thread
underwing - Krystal Flash pearl
wing/head - deer hair dyed olive
hackle - grizzly dyed olive

Part 1

Trim out hackle underneath (optional)

Mash barb, start thread gap width back from eye

Clean, stack, measure (hook length + gap width) a clump of deer hair; tie in at eye, tips facing forward, trim butts, wrap to bend

Clean, stack, measure (gap width past bend) another clump of deer hair; tie in, wrap to head butts, creating smooth thread body, trim