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.

The Clark's Fork of the Yellowstone River in Wyoming

Stream photos

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Glossosoma (Little Brown Short-horned Sedge) Caddisfly Larva Glossosoma (Little Brown Short-horned Sedge) Caddisfly Larva

Dorsal view of a Glossosoma (Glossosomatidae) (Little Brown Short-horned Sedge) Caddisfly Larva from the Yakima River in Washington

I caught this tiny larva without a case, but it seems to key pretty clearly to to Glossosomatidae. From there, the lack of sclerites on the mesonotum points to either Glossosoma or Anagapetus. Although it's difficult to see in a 2D image from the microscope, it's pretty clear in the live 3D view that the pronotum is only excised about 1/3 of its length to accommodate the forecoxa, not 2/3, which points to Glossosoma at Couplet 5 of the Key to Genera of Glossosomatidae Larvae.

11 Recently Added Photos

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 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.

Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington

Lateral view of a Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington

Ruler view of a Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington The smallest ruler marks are 1 mm.

Dorsal view of a Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington

Ventral view of a Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington

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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