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Rhithrogena morrisoni (Western March Brown) Mayfly Nymph Pictures

 Size - (excluding tails) - 12 mm
Status at time of photo - preserved, but photographed within days of capture.

W. C. Day, Aquatic Insects of California differentiates morrisoni nymphs by submedian pale dots on tergites (
One tergite of this Isonychia bicolor mayfly spinner is highlighted in red.
One tergite of this Isonychia bicolor mayfly spinner is highlighted in red.
Tergite: The top (dorsal) part of a single segment on an insect's abdomen when it consists of a single chitinous plate (sclerite), or an individual sclerite if the segment has more than one.
)
8 & 9, which look to be in evidence. This is one of the "super-hatches" on this river that can be prolific March through April.

Entoman


This mayfly was collected from the Lower Yuba River on March 3rd, 2011 and added to Troutnut.com on November 1st, 2011.

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Rhithrogena morrisoni (Western March Brown) Mayfly Nymph from the Lower Yuba River in California
AuthorEntoman
CameraCanon PowerShot A490
View Full SizeView Full Size (4.5X larger)
AddEmail
Rhithrogena morrisoni (Western March Brown) Mayfly Nymph from the Lower Yuba River in California
AuthorEntoman
CameraCanon PowerShot A490
View Full SizeView Full Size (2X larger)
AddEmail
Rhithrogena morrisoni (Western March Brown) Mayfly Nymph from the Lower Yuba River in California
AuthorEntoman
CameraCanon PowerShot A490
View Full SizeView Full Size (4.5X larger)
AddEmail
Rhithrogena morrisoni (Western March Brown) Mayfly Nymph from the Lower Yuba River in California
AuthorEntoman
CameraCanon PowerShot A490

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