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Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin
Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.

Case view of a Pycnopsyche guttifera (Limnephilidae) (Great Autumn Brown Sedge) Caddisfly Larva from the Yakima River in Washington
It's only barely visible in one of my pictures, but I confirmed under the microscope that this one has a prosternal horn and the antennae are mid-way between the eyes and front of the head capsule.

I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.

The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.

Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
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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Brown Quill Spinners

Like most common names,"Brown Quill Spinner" can refer to more than one taxon. They're previewed below, along with 5 specimens. For more detail click through to the scientific names.

Mayfly Species Siphlonurus alternatus

These are sometimes called Brown Quill Spinners.
This species occasionally produces important spinner falls. Its spinners may join the swarms of Siphlonurus quebecensis or Siphlonurus rapidus, amplifying the importance of all three species.
Lateral view of a Female Siphlonurus alternatus (Siphlonuridae) (Gray Drake) Mayfly Spinner from the Gallatin River in Montana
I'm tentatively classifying this one as Siphlonurus alternatus, because it seems to fit that species best in the old keys in Needham's Biology of Mayflies, but I'm hesitant because I can't find documentation that southwest Montana or the surrounding area is within the species' range, although they are widely distributed throughout eastern North American and western Canada.
Dorsal view of a Siphlonurus alternatus (Siphlonuridae) (Gray Drake) Mayfly Nymph from the Namekagon River in Wisconsin

Mayfly Species Siphlonurus quebecensis

These are sometimes called Brown Quill Spinners.
This is the Siphlonurus species I have encountered most frequently on Eastern trout waters. I often find its spinners swarming in a mix with Siphlonurus alternatus, and I have read that Siphlonurus rapidus may join these groups as well.
Female Siphlonurus quebecensis (Siphlonuridae) (Gray Drake) Mayfly Dun from unknown in Wisconsin
This one hatched in my house after I brought some nymphs home to photograph.
Lateral view of a Male Siphlonurus quebecensis (Siphlonuridae) (Gray Drake) Mayfly Spinner from the Namekagon River in Wisconsin
Siphlonurus mayfly nymph. These mayflies are known as strong swimmers that maneuver like minnows across the stream bottom

Artistic view of a Siphlonurus quebecensis (Siphlonuridae) (Gray Drake) Mayfly Nymph from the Delaware River in New York

Brown Quill Spinners

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