Header image
Enter a name
Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York
Blue-winged Olives
Baetis

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

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.

Female Ephemerella excrucians (Pale Morning Dun) Mayfly Dun Pictures

Ruler view of a Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Dun from the Henry's Fork of the Snake River in Idaho The smallest ruler marks are 1 mm.
Lateral view of a Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Dun from the Henry's Fork of the Snake River in Idaho
Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Dun from the Henry's Fork of the Snake River in Idaho
Dorsal view of a Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Dun from the Henry's Fork of the Snake River in Idaho
Ventral view of a Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Dun from the Henry's Fork of the Snake River in Idaho

This mayfly was collected from the Henry's Fork of the Snake River in Idaho on July 31st, 2020 and added to Troutnut.com by Troutnut on August 17th, 2020.


Start a Discussion of Dun

Female Ephemerella excrucians (Pale Morning Dun) Mayfly Dun Pictures

Collection details
Location: Henry's Fork of the Snake River, Idaho
Date: July 31st, 2020
Added to site: August 17th, 2020
Author: Troutnut
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy