Winter stonefly hatch

While fishing the weber this winter, sometime around late jan early feb, my brother and i encountered a stonefly hatch. After some research i found out that they are called Taeniopteryx, i call them smokey stones. They are about a half inch long and have black bodies with a smokey grey wing. They hatch on many rivers and are easily recognized as they crawl all over the snow on the banks. I read an article in a mag that said guys had great luck during this hatch on a prince (16). I later was able confirm that as i found myself in the middle of them again in Idaho. I believe that a prince with a grey biot wing and shorter black tail will match even better. Here is a pic of them on my waders, you can click the pic and see more detail. If you see these guys pull out the prince and hold on...