I could only produce this picture from a NZ Fly Fishing site and the quality is a bit fuzzy and too small. But, you get the idea. I really like the looks of this pattern. Olive Green Swannundaze, or how about a lighter brown Swannundaze? Good possibilities here.
Hook: 8-10 long shank (2-3x long)
Body: olive green Swannundaze (how about brown?)
Thorax: olive green Swannundaze
Wingcase: brown turkey, over both body and thorax, then lacquered (could substitute pheasant tail fibers)
Legs: end whisks of turkey wingcase (or, PT fibers)
Head: black thread
I have seen double bodied type flies out of Idaho and Montana, so when I saw this pattern it was immediately familiar. I don’t believe the bodies are separate but simply separated by a thread tie off of the wingcase. Perhaps there could be an underbody to build up a taper? Is his a taper built by tension on the material like the micro tubing patterns? Perhaps if someone knows the name or total technique they could write so it can be shared??