Chocolate Duns

None of the species in this genus are recognized as significant hatches. Nevertheless, I have found their nymphs in my samples in many streams in both the East and Midwest.

According to the Leonards in Mayflies: An Angler's Study of Trout Water Ephemeroptera , this species and Eurylophella bicolor are the two most likely hatches for fly fishermen to encounter in Michigan. Based on my sampling, it seems other species may be more prevalent elsewhere.

This is one of the most challenging mayfly hatches on waters across the country.

Ephemerella dorothea consists of two distinct subspecies (Subspecies: Entomologists sometimes further divide a species into distinct groups called subspecies, which have two lower-case words on the end of their scientific name instead of one. The latter is the sub-species name. For example, Maccaffertium mexicanum mexicanum and Maccaffertium mexicanum integrum are two different subspecies of Maccaffertium mexicanum.) which both produce excellent action. Ephemerella dorothea dorothea is a small species of Sulphur in the East, and Ephemerella dorothea infrequens (formerly Ephemerella infrequens) is one of the two main Pale Morning Dun hatches of the West.

This species, the primary "Sulphur" hatch, stirs many feelings in the angler. There is nostalgia for days when everything clicked and large, selective trout were brought to hand. There is the bewildering memory of towering clouds of spinners which promise great fishing and then vanish back into the aspens as night falls. There is frustration from the maddening selectivity with which trout approach the emerging duns--a vexing challenge that, for some of us, is the source of our excitement when Sulphur time rolls around.

Ephemerella invaria is one of the two species frequently known as Sulphurs (the other is Ephemerella dorothea). There used to be a third, Ephemerella rotunda, but entomologists recently discovered that invaria and rotunda are a single species with an incredible range of individual variation. This variation and the similarity to dorothea make matching this hatch exceptionally tricky.

As the combination of two already prolific species, this has become the most abundant of all mayfly species in Eastern and Midwestern trout streams.

This small and slightly noteworthy mayfly appears during the finest hours of the year. Ernest Schwiebert describes an Ephemerella needhami day in Matching the Hatch:

"It was a wonderul morning, with a sky of indescribable blue and big, clean-looking cumulus clouds, and the water was sparkling and alive. You have seen the water with that lively look; you have also seen it dead and uninviting in a way that dampens the enthusiasm the moment you wade out into the current."

I have not fished a needhami emergence, but the exquisite nymphs show up often (though never abundantly) in my samples.

The Brown Drakes are a favorite hatch of many in the Midwest, and they make a good showing on localized waters across the country. They are usually the first in a series of big drakes which bring large trout to the surface at twilight and into the early hours of the night.