Here is a pattern I tye that with out a doubt has taken a ton of trout. The Henry's Fork Caddis another great Rene Harrop pattern that works well here in the Northeast.I tye these with olive biots mostly but do them in other colors as well.
Recipe for the Henry's Fork Caddis
Hook standard dry fly hook 12-20
Thread olive 6 or 8/0 uni
Body olive goose biot
Wing natural cdc with lemon wood duck over
Thorax a turn or two of peacock
Hackle a few turns of grizzly and trim out the bottom