I have never came across this fly before, but I thought it was a really buggy fly that will fish well. It comes from a saltwater book, but I think this would make a great smallmouth bass fly.
Here is what Morten Hansen of Coastfly had to say about this fly pattern.
“This fly is called “mymfen” and originally it was developed for fishing from bellyboat. It was to be tied with a lot of nonlead wire in front to give a faster sinking fly so you Could fish this over deeper water from the bellyboat. I left out the added weight to be able to fish this on the coast as i am 100 percent sure it Will do great for that as Well! Swipe to see the original fly from the book “seatrout on the coast 2” .”