‘Hex’ hatch is a trout fisherman’s dream

So the question is, I guess, “When is a Green Drake a Green Drake, and when is a Hex a Hex?” You don’t care? Well, in that case, you’re probably just a casual fly fisher of trout. Those of us, whose heroes are fly fishing entomologists, like to know our bugs, for that is how you get to know your trout and how best to seduce them.


A Hex, or if your Latin is good, a Hexagenia limbata, is a bomber-size Mayfly that shows up on Maine trout ponds in mid-summer, usually early July. For a trout, they are a turkey dinner with all the fixin’s — a chance to get the most amount of food for the least amount of effort.


To a trout-loving fly fisherman, a Hex hatch is an adrenaline rush — a sight to behold. In fact, 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. Truth is my experience with Hex hatches can be counted on one hand. Still, one July Hex encounter stands out in my memory.


Diane and I were camped at one of  Wiggie Robinson’s favorite trout ponds in early July. The fishing had been slow all day. Then just before dark the Hexes began to bust through the still surface of the pond. Soon the pond was covered with these big-winged, lime-green duns. It looked like a flotilla of small sailboats “in irons,” becalmed by the dying breeze.


Blup, Blup, Blup. The feeding began and the pond was peppered with surface feeding trout dimples wherever you looked. The trout gorged themselves for about an hour. They also took our big White Wulffs without hesitation. Then the Hexes disappeared as fast as they came on, and the fishing slowed accordingly.


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 went behind the mountain, 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?”


I put the aforementioned question to Tom Fuller. Fuller, a seasoned fly fisher, outdoor writer, author, and aspiring entomologist, has written an informative new book, “Eastern Hatches.” Here is his answer:


“The differences between the Eastern Green Drake (3 tails on the dun) and the Hex hatch (two tails on the dun) are at best subtle. The Eastern has mottled wings, the Hex doesn’t have the mottling, but does have veins. Coloration and size really depend on the waters where they’re found and the fertility. The real difference is the double gills found on body segment #1 on the Hex. The Eastern nymph has single gills on body segments 1 through 7.


As Fuller pointed out, when these big bugs are on the water, the fish are really fired up and just about any big pattern will work. Wulffs, a large Adams, or a Hornberg never disappoint when the Hex hatch is on. 


As always the best of trout fishing in Maine begins to fade as summer comes on and water temperatures drive the brookies deep into the spring holes. But there is still time, especially because of the late spring and slow-warming waters. The farther north in Maine you go the 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.


So whether your Green Drake is a Hexagenia limbata or an Ephemera guttulata, the trout don’t seem to care. And that’s what counts.


The author is editor of the “Northwoods Sporting Journal.” He is also a Maine guide and host of a weekly radio program — “Maine Outdoors” — heard Sundays at 7 p.m. on “The Voice of Maine News – Talk Network.” He has authored three books; online purchase information is available at or at

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