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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 Baetis tricaudatus (Blue-Winged Olive) Mayfly Nymph Pictures

This specimen and many like it were found with other specimens I found to be duller-colored females of the same species. I wasn't aware of such a difference between male and female nymphs in Baetids, but all the morphological characteristics I checked in the key were the same, and the color patterns are, too -- just not the brightness.

Ruler view of a Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington The smallest ruler marks are 1 mm.
Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Ventral view of a Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Dorsal view of a Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington
Detached labium and labial palps.

Male Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington

This mayfly was collected from the Yakima River in Washington on April 9th, 2021 and added to Troutnut.com by Troutnut on April 12th, 2021.


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Male Baetis tricaudatus (Blue-Winged Olive) Mayfly Nymph Pictures

Collection details
Location: Yakima River, Washington
Date: April 9th, 2021
Added to site: April 12th, 2021
Author: Troutnut
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