From a fly collection, most of which were acquired during the 1970s. This is a beautifully tied small stonefly fly nymph with a light brown Swannundaze body, dubbed thorax, partridge legs and biot tails. Looks to me like it might be a size 12 hook. Unknown tier. This fly can be used for fishing but a more practical use would be as a fly tying reference sample for copying or mounted in some kind of shadow box for display purposes.