Here is a pattern developed some 15 to 18 years ago by Hans van Klinken. It's a great parachute tie that rides low in the water.

Hook: Partridge GRS15ST, size 14-8 as an alternative use a TMC - 200R size 10-16 shank bent 1/3 way back from the eye
Thread: Uni-thread, 8/0, grey or tan or olive for body. Danville's Spiderweb for the parachute
Body: Light-tanor olive
Wing: One strand of white poly-yarn
Thorax: Three strands of Peacock herl
Hackle: Blue dun hackle

Notes:

• The ability to see this pattern on the water is important. Tie the wing long so that it can be spotted
  
• Use premium quality hackles, and give at least five full turns as the whole fly supported solely by the fibres of the parachute hackle. Wind from the top down.
  
• Do not use floatant on the body only the wing.