Ribbing Brown thread perdigon thread (thread / perdigon body thread)
Hackle Yellow + dun hackle (CDC in split thread)
Second hackle Yellow second hackle (teal duck flank)
How to tie it
Lay a yellow thread base. On this fly the thread IS the body (no dubbing, no feather) so take the time to build a smooth, slim, slightly tapered underbody.
Rib forward with brown thread in open turns for segmentation.
Split the micro thread, load it with CDC in yellow and dun, and spin it into a fine hackle rope. The micro split-thread technique is what lets this dressing stay delicate at size 14-16.
Wrap the CDC hackle at the thorax, then add a second, sparser hackle of teal duck flank dyed yellow in front of it.
Trim the CDC underneath the thorax flat. This is the detail that makes the fly sit down on the surface with a clean water print instead of tipping over on its side.