If you've fished for Trout before, chances are pretty high you've used a BWO imitation of some sort in the past. The Blue Wing Olive is present in many North American river systems.
Hook: TMC 100
Tail: Dark Blue
Body: Dun Hackle Fibers
Body Abdomen: Medium Olive Brown Dubbing
Body Wing Case: Dark Blue Dun Hackle Tri
Hackle: Dark Blue Dun