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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.

Male Cinygmula uniformis Mayfly Spinner Pictures

The identification of this specimen is not positive because some of the key characteristics conflict. The uniform amber tint of the wings and the rusty-colored mid-ventral markings on some of the abdominal sternites point to Cinygmula uniformis, but I could not locate the small ventral subapical spines on the penes that are supposed to also diagnose that species (the ones visible in the pictures aren't the ones I'm talking about). If I prioritize that characteristics, this would probably be Cinygmula mimus, but then the wing and sternite shading/markings are wrong.

This mayfly was collected from the South Fork Snoqualmie River in Washington on May 22nd, 2022 and added to Troutnut.com by Troutnut on May 24th, 2022.

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