Ribbing Brown permanent marker (perdigon body thread)
Wing loop Mayfly yellow (CDC feathers)
Hackle Mayfly yellow (mallard/teal duck)
Thorax Yellow mcflylon (mallard puff)
How to tie it
Start the yellow thread and run a smooth base to the bend.
Tie in pheasant tail barbs as a short tail, then tie in the brown perdigon thread for the rib.
Wrap the yellow Mojo Yarn forward to the 65% mark. The yarn is translucent, so the yellow underbody glows through it and gives the body the segmented, backlit look of a real danica coming out of its shuck.
Rib forward with the brown perdigon thread in 5-6 evenly spaced turns and tie off.
Tie in CDC in mayfly yellow as a standing wing loop over the thorax. The loop, rather than a full upright wing, is what keeps this fly in the film instead of on top of it.
Wrap a sparse collar of mallard or teal dyed mayfly yellow as the hackle, then finish the thorax with a yellow mallard puff.
Whip finish. The fly should hang with the body under the surface and the CDC loop in the meniscus.