Troutnut gives stoneflies less significance beyond the craziness of May-June on Western streams/rivers. The patterns associated with stoneflies, like most insect patterns, run from the simple to the complex. The Brook’s Stone, Montana Stone or Bitch Creek catch many fish. The above pattern was a simple tie. Leave off the backstrap/wingcase of turkey and you would have a Brooks Stonefly. The Golden Stonefly and Little Yellow Stonefly are Summer time staples. Stonefly patterns are often used as sources of weight to sink other nymphs, where weight cannot be affixed to the leader/tippet.
The above pattern has a goose biot tail. Copper wire ribbing is wrapped over a turkey backstrap and black dubbed abdomen. The same dubbing material is used to dub a heavier thorax, which was over wrapped with black hen hackle and that covered by the same extended turkey fibers to form the wingcase. I have used black, fuzzy yarn before to form the abdomen/thorax, as opposed to dubbing. Hackle fibers could be used for the tail rather than the goose biots, although the biots look more realistic for a stonefly nymph and are more durable. The biots (tail) must be spread and not collapsed. Here is a tutorial that shows the attachment of the biots.