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.
This specimen resembled several others of around the same size and perhaps the same species, which were pretty common in my February sample from the upper Yakima. Unfortunately, I misplaced the specimen before I could get it under a microscope for a definitive ID.
Millcreek on Sep 17, 2015September 17th, 2015, 2:25 pm EDT
These nymphs were identified to genus using Merritt, Cummins and Berg (2008) as well as Buglab's "Key to Western Baetidae". They were keyed to species using Day's "New Genera of Mayflies From California" 1955, http://www.ephemeroptera-galactica.com/pubs/pub_d/pubdayw1955p121.pdf where it is described as Paracloeodes abitus (a synonym of Paracloeodes minutus). These were found in the Russian River, CA.
It's found in warm shallow water with a substrate of small gravel with a medium amount of algae attached. It's usually found in September.
The main ways of telling it apart from the other Baetidae are smaller size (3.5 - 4 mm), the claws being half the length of the tarsi and a labium shaped as shown above.
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