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.

Stream photos

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Female Hydropsyche (Spotted Sedge) Caddisfly Adult Female Hydropsyche (Spotted Sedge) Caddisfly Adult

Lateral view of a Female Hydropsyche (Hydropsychidae) (Spotted Sedge) Caddisfly Adult from the Columbia River in Washington

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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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Little Western Blue-Winged Olives

This common name refers to only one species. Click its scientific name to learn more.

Mayfly Species Attenella margarita

These are sometimes called Little Western Blue-Winged Olives.

Though having a national distribution, this species is considered by angling authorities to be important only in the West. In localized waters where it is abundant, it can be a significant hatch.

Female Attenella margarita (Little Western Blue-Winged Olive) Mayfly Dun

6 Pictures

Lateral view of a Female Attenella margarita (Ephemerellidae) (Little Western Blue-Winged Olive) Mayfly Dun from Willowemoc Creek in New York

I found this dun unusually late in the year for anything in the Ephemerellidae family in the East. It's also small for that family.

Collected September 3, 2006 from Willowemoc Creek in New York

Added by Troutnut on October 3, 2006

Collected September 3, 2006 from Willowemoc Creek in New York and added by Troutnut on October 3, 2006

Attenella margarita (Little Western Blue-Winged Olive) Mayfly Nymph

7 Pictures

Dorsal view of a Attenella margarita (Ephemerellidae) (Little Western Blue-Winged Olive) Mayfly Nymph from the East Fork Big Lost River in Idaho

Notes from the microscope on the ID: Maxillary palp is present, distinctly 2-segmented, but very small. Gills on segment 4-7. This specimen has some unfortunate damage to the abdomen, but it's the only one I found in my sample.

Collected August 2, 2020 from the East Fork Big Lost River in Idaho

Added by Troutnut on August 19, 2020

Collected August 2, 2020 from the East Fork Big Lost River in Idaho and added by Troutnut on August 19, 2020