This pattern, which appears to have originated in Norway, has a long string of successes to its name. You can fish it as slowly as you like because its wing is so mobile, but it still has enough presence in fast water.
Tube: Clear plastic
Tag: Mirage tinsel
Body: Red or chartreuse Glo-Brite floss
Wing: Black fox or similar mobile hair
Flash: Mirage Flashabou
Head: Black
Eyes: Small dome eyes superglued and varnished over
Try this low-riding Mayfly Dun for fussy trout that refuse a high-riding dry-fly.