Tricos

Tricorythodes or Tricos are members of the crawler group of mayflies. There are nine species of Tricorythodes found in the western states. Only one Tricorythodes minutus is of importance to fly fishers. Tricos are the smallest mayflies in North America, but their hatches and spinner falls are so heavy that the largest trout in the stream will move up to feed on the surface. Their principal importance is in the spinner stage, when they can coat the surface and get trout to start feeding heavily. The duns, especially the females, can be important during early morning hatches. If you don’t get out early you may be missing the most fishable part of the hatch. The Tricos males and females are slightly different in size and quite different in color.