The Killer Mayfly Nymph is a great pattern as a dropper below a heavier nymph pattern. If you have picky fish, the realistic profile of this pattern works extremely well. It works on just about every trout stream, from the Bighorn River to Rapid Creek. Tie it in sizes 16-22.
Hook: Daiichi 1270
Thread: 70 Denier Black or Olive
Abdomen: Micro Tubing or D-Rib
Wing Case: Medallion Sheeting
Thorax: UV Ice Dubing
Legs: Brahma, India Hen, or Partridge