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Blue-winged Olives

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.

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Stenonema vicarium (March Brown) Mayfly Nymph Pictures

I keyed this nymph to Stenonema fuscom, which is now synonymized with Maccaffertium vicarium. However, the size, markings, and time of year make me very skeptical of this identification.

This mayfly was collected from the Bois Brule River in Wisconsin on June 9th, 2005 and added to Troutnut.com by Troutnut on May 26th, 2006.

Discussions of this Nymph

M. vicarium?
8 replies
Posted by Entoman on Mar 26, 2012
Last reply on Jul 2, 2012 by Gutcutter
You were right about the markings, Jason. This is one of the paler Summer Cahill species, probably mexicanum. The inverted "U" tergal markings are very distinctive (moved to mexicanum).

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Stenonema vicarium (March Brown) Mayfly Nymph Pictures

Collection details
Location: Bois Brule River, Wisconsin
Date: June 9th, 2005
Added to site: May 26th, 2006
Author: Troutnut
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