Mayfly Species Ephemera guttulata (Green Drake)

Where & when

This hatch begins in Pennsylvania in late May and moves into the Catskills through early June. Mid to late June sees Green Drake action in the Adirondacks and other northern New England rivers.

Hatching behavior

Green drakes nymphs swim to the surface and emerge from their shucks very quickly. Ernest Schwiebert describes the difficulty this gave him in trying to catch a nymph:


This haste makes emerger patterns unimportant, but luckily the duns take a long time to get off the water. They flutter around and make several awkward attempts, drawing explosive strikes from trout. Hackled imitations that can be twitched to match this behavior are popular.

Knopp and Cormier write that the best hatches happen during "sustained periods of warm weather."

Spinner behavior

These spinner falls can be extremely intense and they are the most anticipated part of the Green Drake action. They return to mate about three days after emerging as duns.

Just like Ephemera simulans, Ephemera guttulata spinners in the air do not always mean spinners on the water. Subtle shifts in weather may push promising spinner clouds of both species back into the trees for the night. This usually happens when they are still gathering at treetop level. Once the swarms descend and you find yourself surrounded by them, they are almost sure to fall on the water, and good fishing will follow unless the trout have just filled up on nymphs and duns during the hatch.

The spinners are known as "Coffin Flies" and they are black and white. They look like a completely different species than the greenish yellow duns.

Nymph biology

Most writers say Green Drakes tend more toward the silty habitats of Hexagenia than do Ephemera simulans and Ephemera varia. It does not, however, require the same vast beds of silt for a good hatch, and the nymphs may do well in small patches of silt which pile up in the quiet spots in pocket water and rocky pools. They are reported to inhabit sand and fine gravel in sufficiently fertile streams. In Ted Fauceglia's recent book Mayflies he says they are actually more abundant in this typical Ephemera habitat.

Ephemera guttulata Fly Fishing Tips

The mature nymphs of this species are darker than the yellow bodies of other Ephemera nymphs. Ernest Schwiebert described them as "dark greyish-brown."

The males are smaller than the females, and both genders vary greatly in size depending on the fertility of the water. You should size your flies based on naturals you collect or on the local fly shops; don't just buy a few from a national outlet and expect them to match your river's hatch.