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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.

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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Updates from June 18, 2023

Photos by Troutnut from Mystery Creek #199 in Washington

Mystery Creek # 199 in Washington
Naneum Creek

From Mystery Creek # 199 in Washington

Closeup insects by Troutnut from Mystery Creek #199 in Washington

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.
Dorsal view of a Ameletus velox (Ameletidae) (Brown Dun) Mayfly Nymph from Mystery Creek #199 in Washington
This Ameletus has puzzled me since I found their exuviae four years ago. Using the key in Larvae and adults of Ameletus mayflies (Ephemeroptera: Ameletidae) from Alberta this appears to key to Ameletus velox. It also sort of matches the color pattern on abdominal segments 6-7 from their figure 20C, which their text mentions as another identifying characteristic. However, one characteristic ("incisor area of left mandible with second denticle much smaller than first") doesn't seem to match. Also, velox is reportedly among the largest Ameletus species, but not quite as large as this nymph. My best guess is still that it represents a bit of undocumented variation on velox.
Dorsal view of a Kogotus (Perlodidae) Stonefly Nymph from Mystery Creek #199 in Washington
This one pretty clearly keys to Kogotus, but it also looks fairly different from specimens I caught in the same creek about a month later in the year. With only one species of the genus known in Washington, I'm not sure about the answer to this ID.

Updates from June 4, 2023

Closeup insects by Troutnut from the Columbia River in Washington

Lateral view of a Female Hydropsyche (Hydropsychidae) (Spotted Sedge) Caddisfly Adult from the Columbia River in Washington

Updates from May 28, 2023

Closeup insects by Troutnut from Sears Creek in Washington

Dorsal view of a Amphizoa (Amphizoidae) Beetle Larva from Sears Creek in Washington
This is the first of it's family I've seen, collected from a tiny, fishless stream in the Cascades. The three species of this genus all live in the Northwest and are predators that primarily eat stonefly nymphs Merritt R.W., Cummins, K.W., and Berg, M.B. (2019).
Lateral view of a Coleoptera (Beetle) Insect Larva from Sears Creek in Washington
Dorsal view of a Doroneuria baumanni (Perlidae) (Golden Stone) Stonefly Nymph from Sears Creek in Washington

Updates from May 26, 2023

Closeup insects by Troutnut from the Yakima River in Washington

Artistic view of a Perlodidae (Springflies and Yellow Stones) Stonefly Nymph from the Yakima River in Washington
This one seems to lead to Couplet 35 of the Key to Genera of Perlodidae Nymphs and the genus Isoperla, but I'm skeptical that's correct based on the general look. I need to get it under the microscope to review several choices in the key, and it'll probably end up a different Perlodidae.

Not even fishing this time

By Troutnut on May 5th, 2023
My wife and I went to the the Camlann Medieval Village in the foothills of the Cascades east of Seattle last night, which was the last place I expected to collect bugs for the website. But there was small creek rushing through the valley below, and reflexes kicked in when this stonefly flew past my face. It mostly survived the ride home in a random pocket of my wife's purse, minus a couple legs and antennal segments. It made for some good pictures, especially closeups of the four red mites riding its back.

Closeup insects by Troutnut from Harris Creek in Washington

Lateral view of a Female Sweltsa borealis (Chloroperlidae) (Boreal Sallfly) Stonefly Adult from Harris Creek in Washington
I was not fishing, but happened to be at an unrelated social event on a hill above this tiny creek (which I never even saw) when this stonefly flew by me. I assume it came from there. Some key characteristics are tricky to follow, but process of elimination ultimately led me to Sweltsa borealis. It is reassuringly similar to this specimen posted by Bob Newell years ago. It is also so strikingly similar to this nymph from the same river system that I'm comfortable identifying that nymph from this adult. I was especially pleased with the closeup photo of four mites parasitizing this one.

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