Perhaps you would be interested in the history behind Borger's Strip Nymph and Borger's Strip Leech.
Royce Dam is one of the best fly tiers in the USA. He was awarded the highest fly tying award in the USA in 1994, the Federation of Fly Fishers Buz Buszek Memorial Fly Tying Award.
http://www.fedflyfishers.org/Portals/0/FlyTyingGroup/FTGDocuments/Buszek/1994_RoyceDam.pdf
Royce was an instructor at the Midwest Fenwick Fly Fishing School where I learned to fly cast from Gary Borger, who was the midwest director of the schools.
Royce relates the story of how he showed Gary his "strip fly" during one of the Fenwick Schools. It is in Royce's book, The Practical Fly Tier.
The Practical Fly Tier: No Nonsense Patterns and Techniques for Wet and Dry ... - Royce Dam, Mark Van Patten - Google Books
"I had been an instructor at Gary Borger's Fly Fishing Schools for several years before I showed him any of my flies. That changed after the conclusion of one of his schools. It was customary for the instructors to gather after class to fish in the casting ponds. The ponds were filled with sone very nice fish for the students to sharpen their skills on. Catch and release was always the order of the day. That’s why the fish were as big as they were. And I think that is why they were as selective as any I have fished over.
I decided to tie on a fly I had developed over the years earlier for just such a difficult situation. I called it the Strip Fly and little did I know that the fly would be known to anglers everywhere.
Gary walked over to me while I was landing a particularly nice fly and watched as I removed the fly and returned the fish to the water.
‘What the heck do you call that fly?’, he asked.
‘The Strip Fly’, I answered. I told him that I tied it as a nymph, a leech, and as a streamer and had great success all three ways. Gary liked the ideas and used the nymph and leech versions himself. When he wrote the book, Naturals, he described the pattern. It wasn’t long before strip patterns with various named hit the market. Most of them used rabbit fur in the place of muskrat strip that I used on my flies.
Today anglers are tying fur strip patterns for man different species of fish…..”
In Designing Trout Flies, pg 87, Gary Borger describes Royce dam’s contribution to the development of the strip nymph:
“The burrowing nymphs .. during hatch periods are most vulnerable to predation. They are suprisingly good swimmers their waving gills and undulating abdomens beating powerfully. It is this snakelike movement that so attracts the trout….. A long marabou tail made a good pulsing body but it lacked the singular up and down undulations of the natural. What to use to simulate this unique movement?
In this case the answer was provided by Royce Dam, a good friend and gifted, inventive tier. It was the spring of 1976 and we were teaching a fly fishing school in southeastern Wisconsin.After the day’s activities, Royce tied on a fly and flipped it into the water to show me its action. The fly was a muskrat nymph to which Royce had added a wing made of tanned muskrat hide with the fur still attached…… That strip of hide gave the exactly the fluid undulations I was looking for. Such movement would be a decidedly strong trigger of the trouts predatory instinct. It was an easy matter top replace the marabou tail if mu burrowing nymph pattern with a strip of hide and the Strip Nymph was born.”
Royce is no ordinary fly tier. He ties full dress salmon flies, salt water patterns, packed hair bass bugs. Here are some of his shadow box flies that I have displayed in my tying room.
