I finally had time recently to tie Craig Mathew's great mayfly pattern in front of Tim Flagler's camera. I've written about this pattern many times over the last few years for good reason; it works very well when trout are feeding on olives. It's fairly easy to tie with only three materials that are readily available.
Hook: Dai Riki #125 size 18 -24
Thread: 6/0 Olive Danville
Wing: Dun dyed deer hair - fine
Shuck and Wing: Light dun Zelon or substitute such as EP Trigger Fibers or Antron
Thorax: Dark olive dubbing - I like Australian opossum or beaver
Sharpen your hook.