Andy Carlson, a guide on the Bitterroot River in Montana came up with this pattern which is very similar to a Parachute Adams dry fly, but with a dubbed purple body. A generic mayfly attractor pattern, the Purple Haze has gotten quite popular throughout the country.
Hook: #10-16 Dry fly
Thread: Black (or purple if you have it)
Tail: Moose hair
Body: Purple dubbing
Post: Calf hair or synthetic Para Post
Hackle: Brown and grizzly rooster