Header image
Enter a name
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.

Dorsal view of a Setvena wahkeena (Perlodidae) (Wahkeena Springfly) Stonefly Nymph from Mystery Creek #199 in Washington
As far as I can tell, this species has only previously been reported from one site in Oregon along the Columbia gorge. However, the key characteristics are fairly unmistakable in all except for one minor detail:
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.
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.
Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Calloway has attached this picture to aid in identification. The message is below.
Asheville, NC

Posts: 5
Calloway on Jul 9, 2008July 9th, 2008, 7:32 am EDT
Got some guys wanting to say the following is a Hex Limbata. I'm not sure what it is but a little light in color for the Hex's I am familar with. Would like to say golden Drake but only two tails.

Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Jul 9, 2008July 9th, 2008, 9:28 am EDT

This is Hexagenia limbata. That species displays tremendous variation in appearance over its transcontinental range. Sometimes the observed differences are due to this variation, sometimes they are due to the difference in coloration between male and female, and sometimes they are attributable to capturing the insect at various stages of darkening following a molt. Teneral (freshly emerged) insects will be much paler and will have less distinct markings than those that have had time to age and darken. This is true of nymphs, duns, and spinners. Your mayfly is a female imago (spinner) that has yet to express her egg packets.
Wiflyfisher's profile picture

Posts: 622
Wiflyfisher on Jul 9, 2008July 9th, 2008, 9:56 am EDT
To add to what Gonzo is saying, see the photo below of two Hexs I captured this year...

Quick Reply

Related Discussions

Last Reply
Mar 22, 2013
by Jmd123
Jun 17, 2007
Sep 3, 2007
by Gene
Troutnut.com is copyright © 2004-2023 (email Jason). privacy policy