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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.

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.

Male Serratella micheneri (Little Dark Hendrickson) Mayfly Nymph Pictures

This specimen has tarsal claws with 7 denticles and tubercles on abdominal segments 4-7 only. It keys to Serratella micheneri, as do some other specimens from the same collection that lacked the dorsal stripe.

Ruler view of a Male Serratella micheneri (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from Mystery Creek #199 in Washington The smallest ruler marks are 1 mm.
Dorsal view of a Male Serratella micheneri (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from Mystery Creek #199 in Washington
Male Serratella micheneri (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from Mystery Creek #199 in Washington
Male Serratella micheneri (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from Mystery Creek #199 in Washington
Male Serratella micheneri (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from Mystery Creek #199 in Washington
Male Serratella micheneri (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from Mystery Creek #199 in Washington
Male Serratella micheneri (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from Mystery Creek #199 in Washington
Male Serratella micheneri (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from Mystery Creek #199 in Washington
Male Serratella micheneri (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from Mystery Creek #199 in Washington

This mayfly was collected from Mystery Creek #199 in Washington on July 28th, 2019 and added to Troutnut.com by Troutnut on July 30th, 2019.

Discussions of this Nymph

Ephemerella tibialis
2 replies
Posted by Millcreek on Dec 24, 2019
Last reply on Dec 26, 2019 by Millcreek
This nymph appears to be Ephemerella tibialis formerly known as Serratella tibialis. Check out Allen and Edmunds; http://www.ephemeroptera-galactica.com/pubs/pub_a/puballenr1963p583.pdf

Also check https://bugguide.net/node/view/696565/bgpage and https://bugguide.net/node/view/876178

Edit: Just noticed the other two Serratella micheneri sets of photos. These also appear to be Ephemerella tibialis.

Also spotted these two sets of photos where you identified the same or a similar nymph as Ephemerella tibialis.

http://www.troutnut.com/specimen/1176

http://www.troutnut.com/specimen/1178

Start a Discussion of Nymph

Male Serratella micheneri (Little Dark Hendrickson) Mayfly Nymph Pictures

Collection details
Location: Mystery Creek #199, Washington
Date: July 28th, 2019
Added to site: July 30th, 2019
Author: Troutnut
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