**Male Rhithrogena morrisoni (Western March Brown) Mayfly Spinner Pictures**

Mayflies

Caddisflies

Stoneflies

Classification

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Heptageniidae (March Browns, Cahills, Quill Gordons)

» Genus Rhithrogena

» Species morrisoni (Western March Brown)

This mayfly was collected from the South Fork Snoqualmie River on June 22nd, 2017 and added to Troutnut.com on June 23rd, 2017.

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Male Rhithrogena morrisoni (Western March Brown) Mayfly Spinner from the South Fork Snoqualmie River in Washington

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Recent Discussions of this Spinner

Second opinions on this one's ID? 3 Replies »

Posted by Troutnut on Jun 23, 2017

Last reply on Jul 5, 2017 by Crepuscular

I tentatively keyed it out to Rhithrogena morrisoni based on Needham's Biology of Mayflies, but I'm not completely sure. Roger's website lists Rhithrogena emerging in Washington in March and April, and this one was collected June 22nd. But this did come from high up in a mountain stream after a year of very heavy snowpack, so it might be that far behind schedule. It also looks very much like the specimen Bob Newell posted from eastern Washington. What do Roger and others think?

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