A white and black thorax dry fly is never a bad choice. The dark body paired with brown hackle helps make this a truly universal mayfly imitation. Sometimes you know the colors of the mayflies, and sometimes you don’t, either way, this mayfly pattern will catch trout during the season. This one floats great above the water and benefits from a dead drift over-feeding trout. The black and white thorax helps to get your fly box to the place it should be.