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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 Amphizoa (Amphizoidae) Beetle Larva from Sears Creek in Washington
This is the first of it's family I've seen, collected from a tiny, fishless stream in the Cascades. The three species of this genus all live in the Northwest and are predators that primarily eat stonefly nymphs Merritt R.W., Cummins, K.W., and Berg, M.B. (2019).
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 Rhithrogena virilis Mayfly Spinner Pictures

I'm fairly sure this is a specimen of Rhithrogena virilis based on closeup examination of the reproductive anatomy under the microscope (not shown in photos). The other other species of Rhithrogena this large is Rhithrogena flavianula, but the key in Needham's Biology of Mayflies mentions annulation in the abdomen (visible in some images on bugguide.net) more distinct than that on this specimen.

The body and front wing were both about 15.5 mm long, while the cerci were 40 mm long.

There's a pale amber tinge to the anterior areas of the wings, which doesn't show up all that well against the blue background.

Lateral view of a Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington
Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington
Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington
Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington
Dorsal view of a Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington
Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington
Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington
Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington
Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington
Tick marks are 1/16". The body and front wing were both about 15.5 mm long.

Ruler view of a Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington The smallest ruler marks are 1/16".
Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington
Ventral view of a Male Rhithrogena virilis (Heptageniidae) Mayfly Spinner from the South Fork Sauk River in Washington

This mayfly was collected from the South Fork Sauk River in Washington on July 5th, 2017 and added to Troutnut.com by Troutnut on July 6th, 2017.


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Male Rhithrogena virilis Mayfly Spinner Pictures

Collection details
Location: South Fork Sauk River, Washington
Date: July 5th, 2017
Added to site: July 6th, 2017
Author: Troutnut
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