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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 Holocentropus (Polycentropodidae) Caddisfly Larva from the Yakima River in Washington
This one seems to tentatively key to Holocentropus, although I can't make out the anal spines in Couplet 7 of the Key to Genera of Polycentropodidae Larvae nor the dark bands in Couplet 4 of the Key to Genera of Polycentropodidae Larvae, making me wonder if I went wrong somewhere in keying it out. I don't see where that could have happened, though. It might also be that it's a very immature larva and doesn't possess all the identifying characteristics in the key yet. If Holocentropus is correct, then Holocentropus flavus and Holocentropus interruptus are the two likely possibilities based on range, but I was not able to find a description of their larvae.
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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Ephemerella aurivillii Mayfly Nymph Pictures

Ventral view of a Ephemerella aurivillii (Ephemerellidae) Mayfly Nymph from Nome Creek in Alaska
Dorsal view of a Ephemerella aurivillii (Ephemerellidae) Mayfly Nymph from Nome Creek in Alaska
Ephemerella aurivillii (Ephemerellidae) Mayfly Nymph from Nome Creek in Alaska
Ruler view of a Ephemerella aurivillii (Ephemerellidae) Mayfly Nymph from Nome Creek in Alaska The smallest ruler marks are 1 mm.

This mayfly was collected from Nome Creek in Alaska on July 10th, 2011 and added to Troutnut.com by Troutnut on July 13th, 2011.


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Ephemerella aurivillii Mayfly Nymph Pictures

Collection details
Location: Nome Creek, Alaska
Date: July 10th, 2011
Added to site: July 13th, 2011
Author: Troutnut
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