I really like this trib nymph, and I've had some success this season when other flies are not working. It is essentially a giant PT with a hot spot for the thorax. Not really imitating a specific thing, more like an egg/attractor nymph all rolled into one. It is not the easiest tie, but it is also not the most difficult so I wouldn't be heart broken to loose a few. When I'm fishing the tribs I always start with simple patterns that I'm not afraid to loose, and gradually use the more complex patterns if the fish are picky. Good luck!