The Stimulator Dry Fly is a great pattern, which was created by Randall Kaufman for Stoneflies on streams. The original pattern was tied with an orange and a yellow body to replicate the Salmon Fly & Golden Stone. This pattern is not only suitable for Stoneflies but in reduced sizes and different colors, perfect for large bodied Caddis as well (October Caddis & Traveling Sedge).
Look at the following two links for very helpful how-to steps for tying the Stimulator:
Now the next step in the learning process, that I always use, is how would I present this fly? That is based not just on what line to use and how to cast it, but most importantly where to cast to. And, that is determined by studying up on where the Stonefly or Caddis flies, that you are copying, reside in the stream, river or lake.
Their habitat, their stages…progression in the life cycle take place in certain types of waters as the stages evolve. So study up on how the stonefly ’emerge’ and when/where they return to the water as well as how the Caddis emerge and return to the waters surface. All that will determine where to cast, even how to cast.
My pattern, above was sloppy in the tail and has less hackle wraps than you will see in the above how to’s. Do it their way! Mix up the abdomen colors: Orange, Yellow, Black, Green, Tan