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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 Setvena wahkeena (Perlodidae) (Wahkeena Springfly) Stonefly Nymph from Mystery Creek #199 in Washington
As far as I can tell, this species has only previously been reported from one site in Oregon along the Columbia gorge. However, the key characteristics are fairly unmistakable in all except for one minor detail:
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.
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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Male Cheumatopsyche (Little Sister Sedge) Caddisfly Adult Pictures

I didn't identify this one directly, but I eventually identified one of several I collected from the same swarms that appeared to be of the same species. (I lost track of which specimen was which in storage.) The microscope pictures come from one of these specimen, not necessarily the same specimen as the DSLR pictures. They key to Cheumatopsyche, and the hind wing venation that separates them from Hydropsyche is pretty clear in the attached picture as well as another specimen I checked under the scope.

This specimen was one of tens of thousands we saw on a July 1st evening on the Madison, beginning with big swarms around every vehicle and tree at the Eight Mile Ford access point and continuing all up and down the river bank. We somehow didn't catch any trout, perhaps because they were stuffed with pupae from when these things emerged. Or maybe we just weren't fishing well. Either way, this one represents a major hatch there.

I somehow forgot to photograph this important specimen against the hooks size chart, but fortunately I preserved a few. The body length is about 6 mm, and total length from head to wingtip is 9 mm.

This caddisfly was collected from the Madison River in Montana on July 1st, 2019 and added to Troutnut.com by Troutnut on July 18th, 2019.


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Male Cheumatopsyche (Little Sister Sedge) Caddisfly Adult Pictures

Collection details
Location: Madison River, Montana
Date: July 1st, 2019
Added to site: July 18th, 2019
Author: Troutnut
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