CDC and Deer Hair Caddis
I can't recall, now, the originator of this pattern, but I do like the idea.
It is hard to see, but there is a looped underwing of CDC beneath the deer hair. This leads to some fibers of the CDC surrounding the fly and the loop might well trap air bubbles.
How timely! We're doing that pattern in my chapter's tying classes in 2 weeks. I need to get more CDC and Elk hair at a show on Saturday.
There is a more common fly called a CDC Elkhair Caddis (actually tied with deer hair) which is quite different. It has a body formed by palmering a CDC feather up to the head, followed by deer hair. In that pattern, once you get to the thorax, the CDC fibers become "free" and they form the legs.
This pattern is quite different.
Thanks Alan, I now see the differences. We'll do the old standby. I may try this version myself.