Stonefly Species Claassenia sabulosa (Golden Stones)

Claassenia sabulosa is the only species in an exclusively western genus. It is also the West's sole representitave in the subfamily Perlinae. Overall, its the least important species among the common western Perlidae . But it is paradoxically the most important at the time of its greatest activity. This is because it is primarily a late Summer/Fall emerger that can be found as late as October in many locations, long after the hatches of its siblings have been relegated to memory.

No other aquatic insect rivals them for size and sheer calorie content during the time of year when they are on the water. The only other truly large aquatic insects that even come close at this time of year are Dicosmoecus caddis, though they usually hatch later. While approaching in wing length, the caddis doesn't come close in body mass. The angler fortunate to come across a major flight of these critters in the fall is apt to have tremendous action as the trout prepare for winter by feeding ravenously.