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.

Firehole River Sunset

From the Firehole River in Wyoming

Stream photos

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Grammotaulius betteni (Northern Caddisfly) Caddisfly Larva Grammotaulius betteni (Northern Caddisfly) Caddisfly Larva

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.

12 Recently Added Photos

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.

Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Rhithrogena impersonata (Dark Red Quill) Mayfly Nymph Pictures

This specimen shows one of two distinct color types of Rhithrogena impersonata nymphs. This type is very reddish, especially in the gills, perhaps a representative of the form formerly known as a separate speciesRhithrogena sanguinea.

Ruler view of a Rhithrogena impersonata (Heptageniidae) (Dark Red Quill) Mayfly Nymph from the Long Lake Branch of the White River in Wisconsin The smallest ruler marks are 1/32".

Rhithrogena impersonata (Heptageniidae) (Dark Red Quill) Mayfly Nymph from the Long Lake Branch of the White River in Wisconsin

Dorsal view of a Rhithrogena impersonata (Heptageniidae) (Dark Red Quill) Mayfly Nymph from the Long Lake Branch of the White River in Wisconsin

Ventral view of a Rhithrogena impersonata (Heptageniidae) (Dark Red Quill) Mayfly Nymph from the Long Lake Branch of the White River in Wisconsin

This mayfly was collected from the Long Lake Branch of the White River in Wisconsin on June 5th, 2005 and added to Troutnut.com by Troutnut on May 24th, 2006.

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References

Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.