Catgut Caddis Pupa CreamPrime Fly Company
I've been tying and fishing this pupa nymph for over 10 years now. I was turned onto this material through the old euro nymphing forum Trout Predator Online and by Aaron Jasper who imported it under "bio-thread".
Catgut is a very translucent material, and you can clearly see the flashy tinsel showing through here. Very buggy.
Makes a great anchor nymph in larger sizes.