Kaufmanns Stonefly Nymph
Imitates the nymphs of the salmonfly (Pteronarcys californica). This fly must be fished on the bottom. Period. So weight it heavily under the body, then flatten the weight with pliers. For extra weight, put on a beadhead. Yes, you're going to lose a lot of flies.
The rubber legs are optional. Vary colors to match the available insects. Most of the big salmonfly nymphs are black, with some chocolate brown ones. The slightly smaller golden stoneflies are more of a mottled tan; use size 8-12 hooks for them.
How to Fish
Dead drift on the bottom with an indicator or tight line presentation. The best areas are bouldery sections, riffles, and just below riffles. If you find a moderatre drop-off just below a riffle, consider yourself blessed.