How to tell the difference between these flies that trout love

By V. Paul Reynolds

The Green Drake: when it shows itself on the surface of a trout pond late in the afternoon, its presence is for the trout angler, a moment of utter delight. It’s a trout bum’s rapture.

The Hex hatch, or the Green Drake hatch, is long awaited by all serious trout anglers. 

To a trout-loving fly fisherman, a Hex hatch is an adrenaline rush, a sight to behold. Like a solar eclipse or an expanse of northern lights in the winter sky, a true Hex hatch on a trout pond counts as one of those special moments in nature. 

For a brook trout, these fabled mayflies are a turkey dinner with all the fixin’s — a chance to get the most amount of food for the least amount of effort.

There is an ongoing debate among Maine anglers about what to call these big bugs. Anglers who know a lot more about entomology than I do say that most of us misname the Hex, calling it a Green Drake, as in, “Hey, Joe — you really missed it. As soon as the sun set, the pond was covered with green drakes. A wicked hatch. Never seen anything to beat it.”

So the question is, I guess, when is a Green Drake a Green Drake, and when is a Hex a Hex?

Leighton Wass, a Vermonter and a trout man who loves Maine, has a book that cuts to the chase on these invertebrates. It’s the quintessential chronicle of big mayflies, titled: “Fishing the Hex hatch.” 

Wass has really done his homework.

He writes, “A gorgeous mayfly owning the scientific name, Ephemera guttulata, a second cousin

to Hexagenia limbata, is also called a green drake, as is the Hex. As you can see, confusion reigns supreme here.”

He goes on: “Confusing the matter more, this mayfly hatches nearly at the same time as Hex mayflies, and both are often found inhabiting the same water body. Also, these two mayflies are similar in size, with E. guttulata being a tad smaller than the Hex.

The easiest way to distinguish the two, with an adult mayfly in hand, is to count the tails. Hex adults have two, and E. guttulata (herein to be called the Eastern Green Drake) have three. Easy peasy. 

Also, if the mayfly you are eyeing has any hint of light green to it at all, it’s an Eastern Green Drake.”

In summary, if a giant mayfly has three tails, a greenish hue and mottled wings, it is no doubt the Eastern Green Drake, Ephemera guttulata. If a big mayfly has two tails, no green coloration and a networked wing design, it’s our megastar, our big cheese, Hexagenia limbata.

Insect hatches are correlated to water temperatures, and so is trout behavior. We know that pond temperatures are unseasonably warm this year thanks to an early spring. However, what we don’t know is what impact this will have on the customary early July Hex hatch, as well as trout-feeding patterns.

The farther north in Maine you go, it’s more likely that the favorable water temperatures will hold a while longer. 

And who knows? 

You might get lucky and get in on a green drake hatch during a cloudy, humid day. You won’t soon forget it, if it happens.

Oh yes, and if you are fortunate enough to hit the Hex hatch, tie on big artificials: Wulffs, Adams and Hornbergs.