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Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin
Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.

Ventral view of a Hydropsyche (Hydropsychidae) (Spotted Sedge) Caddisfly Larva from the Yakima River in Washington
With a bit of help from the microscope, this specimen keys clearly and unsurprisingly to Hydropsyche.
27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.
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This topic is about the Mayfly Species Hexagenia limbata

It starts like a rise of small trout. There are dimples on the surface--fingerling trout eating midges, perhaps. But these are no fish. The water breaks and out pop the yellow sails of a giant Hexagenia dun. Then another. And another. A vortex appears in a flash below the mayfly and it vanishes with a slurp so loud it echoes off the distant bank. A square tail like a shark fin breaks the surface behind the swirl as a brown trout twice the size of your net retreats back to his deeper lair. The Hex hatch is on.

This Midwestern legend plays out every year on calm, dark, humid nights in early July. Anglers who only fly fish once a year drive hundreds of miles to play their part in the drama, while the mayflies themselves make the television news by showing up on doppler radar or calling snowplows out of dormancy to remove layers of Hexagenia (or "Hex") duns from the bridges. In the cold trout rivers of Wisconsin and Michigan, huge nocturnal brown trout whose usual menu consists of smaller brown trout become, for a week or so, prime dry fly quarry.

According to the literature, these are the second largest mayflies in the United States, behind the related Litobrancha recurvata flies. However, there are reports of limbata exceeding 40mm in some locales, which would make them the largest.

Example specimens

AftonAngler
Brule, WI

Posts: 49
AftonAngler on Jun 10, 2006June 10th, 2006, 8:42 am EDT
Well the Hex is right on the cusp of happening...

I have heard rumors of some being spotted on the Nam...about right. I usually set me clock by the Solstice but this season is about ten days to two weeks ahead.

I expect them to show on the Brule anytime too. The next warming trend should usher in some of the big fellows and that will mean no sleep for a couple of weeks for this cat.

I need to sit down and get to tying. I had great success last year with a very 'soft' spinner pattern I dubbed Baby Doll Hex. It was floppy by hex spinner standards and best the pants off the stiff Lucca style patterns that look good int he fly bin but are not for me on the end of my leader when the rubber hits the road!

I also need to reread Galloup's "Cripples and Spinners" - a wealth of info on this aspect of the sport. Great for inspiring tying ideas...



Anyone confirm the reports?
See you on the Water.

Brad Bohen

The Afton Angler
www.BradBohen.com
AftonAngler@BradBohen.com

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