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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.

Dorsal view of a Grammotaulius betteni (Limnephilidae) (Northern Caddisfly) Caddisfly Larva from the Yakima River in Washington
This is a striking caddis larva with an interesting color pattern on the head. Here are some characteristics I was able to see under the microscope, but could not easily expose for a picture:
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
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

I collected this spinner from the trail (old logging road) above a whitewater canyon on a small stream in the Cascades. I'm using its positive ID to put a species ID on a female dun and [speclink id]1217]mature nymph collected on the same trip.

Lateral view of a Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Ruler view of a Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington The smallest ruler marks are 1 mm.
Ventral view of a Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Dorsal view of a Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Dorsal view

Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Ventral view, still attached, with claspers

Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Ventral view

Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Different specimen to show variation -- dorsal view.

Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington
Different specimen to show variation -- ventral view.

Male Rhithrogena hageni (Heptageniidae) (Western Black Quill) Mayfly Spinner from Mystery Creek #249 in Washington

This mayfly was collected from Mystery Creek #249 in Washington on July 4th, 2020 and added to Troutnut.com by Troutnut on July 12th, 2020.


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Male Rhithrogena hageni (Western Black Quill) Mayfly Spinner Pictures

Collection details
Location: Mystery Creek #249, Washington
Date: July 4th, 2020
Added to site: July 12th, 2020
Author: Troutnut
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