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.

I caught a nice brookie a few weeks earlier in this pool at the junction of a split channel in the stream. The huge fallen tree is great cover.

From the Mystery Creek # 23 in New York

Stream photos

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Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva

Lateral view of a Onocosmoecus (Limnephilidae) (Great Late-Summer Sedge) Caddisfly Larva from the Yakima River in Washington

This specimen keys pretty easily to Onocosmoecus, and it closely resembles a specimen from Alaska which caddis expert Dave Ruiter recognized as this genus. As with that specimen, the only species in the genus documented in this area is Onocosmoecus unicolor, but Dave suggested for that specimen that there might be multiple not-yet-distinguished species under the unicolor umbrella and it would be best to stick with the genus-level ID. I'm doing the same for this one.

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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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Male Ephemera simulans (Brown Drake) Mayfly Dun Pictures

This mayfly was collected from Flathead Lake in Montana on July 11th, 2009 and added to Troutnut.com by Bnewell on June 27th, 2011.

Discussions of this Dun

Lifestage

1 replies

Posted by Taxon on Jun 24, 2019

Last reply on Jul 2, 2019 by Troutnut

Hi Bob-

I believe this mayfly to be a female dun (subimago) rather than a spinner (imago) as it was labeled. Do you have a reason to believe I am mistaken?

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