Here is the fly pattern sheet for Stalcup’s CDC Biot Comparadun.
TMC 101, sizes 12 – 24
To match body color
Micro fibetts 4 to 6 split with thread wraps
Fine & Dry color to match
2 to 4 CDC feathers depending on fly size
Stalcup’s CDC Biot Comparadun can be found Shane’s Mayflies “Top to Bottom”. He includes variations in olive, black, and yellow.
Here is a link to a Youtube page from my friend John Sherry – Netknots Fly Fishing of Shane tying the fly.