The Giant Dark Green Drake is the Hexagenia rigida species of the Ephemeridae family. It is very similar to the more famous Hexagenia limbata species. It is found in the Mid-West in slow moving and still waters. We have separate patterns for it because the rigida species are smaller in size and a different color from the “Great Olive-winged Drake”. Like most of the other big drakes this mayfly both hatches and the spinners fall at night. It can also bring on some large trout for the angler who likes to fish in the evening.