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.

A beautiful braided reach of the Sag River, with the Philip Smith Mountains in the Arctic National Wildlife Refuge (ANWR) in the background.

From the Sagavanirktok River in Alaska

Stream photos

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Clostoeca disjuncta (Northern Caddisfly) Caddisfly Larva Clostoeca disjuncta (Northern Caddisfly) Caddisfly Larva

Lateral view of a Clostoeca disjuncta (Limnephilidae) (Northern Caddisfly) Caddisfly Larva from the Yakima River in Washington

This one was surprisingly straightforward to identify. The lack of a sclerite at the base of the lateral hump narrows the field quite a bit, and the other options followed fairly obvious characteristics to Clostoeca, which only has one species, Clostoeca disjuncta.

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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 Rhithrogena hageni (Western Black Quill) Mayfly Spinner Pictures

This specimen was one of several males fluttering around over the river late in the afternoon near the Twin Falls trailhead on May 14. It's pretty clearly the same species as this one collected on June 22 five years earlier.

I also collected a nymph of presumably the same species in the riffle beneath these dancing males.

Lateral view of a Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from the South Fork Snoqualmie River in Washington

Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from the South Fork Snoqualmie River in Washington

Dorsal view of a Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from the South Fork Snoqualmie River in Washington

The anastomosing of the crossveins in the stigmatic area is pretty light compared to other Rhithrogena I've collected. That area is also faintly darker, something harder to see in the photos but fairly conspicuous in the living insect.

Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from the South Fork Snoqualmie River in Washington

Body length 11 mm, wing length 12 mm.

Ruler view of a Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from the South Fork Snoqualmie River in Washington The smallest ruler marks are 1 mm.

Ventral view of a Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from the South Fork Snoqualmie River in Washington

Ventral view

Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from the South Fork Snoqualmie River in Washington

Dorsal view

Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from the South Fork Snoqualmie River in Washington

Artistic view of a Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from the South Fork Snoqualmie River in Washington

Ventral view of the terminalia through my microscope. This was a different specimen of what seems to be the same species, collected on the same river a week later.

Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from the South Fork Snoqualmie River in Washington

Another ventral view of the terminalia through my microscope. This was a different specimen of what seems to be the same species, collected on the same river a week later.

Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from the South Fork Snoqualmie River in Washington

This mayfly was collected from the South Fork Snoqualmie River in Washington on May 14th, 2022 and added to Troutnut.com by Troutnut on May 15th, 2022.

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