Hook:

10 - 16 Tiemco 100 or other standard  dry fly

Thread:

8/0 Uni-Thread Black

Body:

Peacock Herl

Indicator:

Small bunch of Chartreuse Hi-Vis or Polypropylene

Back:

Black 2mm closed cell foam strip

Legs:

Black Span-a-Flex or Sili Legs

One of the all time classic "Trout Foods".  Another staple to trail behind a Hopper or other large attractor - toss in tight to the timber along the banks, especially under overhanging limbs and you will be pleased with the results.