Header image
Enter a name
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 Ephemerella mucronata (Ephemerellidae) Mayfly Nymph from the Yakima River in Washington
This is an interesting one. Following the keys in Merritt R.W., Cummins, K.W., and Berg, M.B. (2019) and Jacobus et al. (2014), it keys clearly to Ephemerella. Jacobus et al provide a key to species, but some of the characteristics are tricky to interpret without illustrations. If I didn't make any mistakes, this one keys to Ephemerella mucronata, which has not previously been reported any closer to here than Montana and Alberta. The main character seems to fit well: "Abdominal terga with prominent, paired, subparallel, spiculate ridges." Several illustrations or descriptions of this holarctic species from the US and Europe seem to match, including the body length, tarsal claws and denticles, labial palp, and gill shapes. These sources include including Richard Allen's original description of this species in North America under the now-defunct name E. moffatae in Allen RK (1977) and the figures in this description of the species in Italy.
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.

Epeorus deceptivus Mayfly Nymph Pictures

Gills #1 failing to meet at the center sterna combined with a lack of small dark single spots mid-femur are characters that differentiate Epeorus deceptivus from Epeorus longimanus.

Epeorus deceptivus (Heptageniidae) Mayfly Nymph from the Gulkana River in Alaska
Epeorus deceptivus (Heptageniidae) Mayfly Nymph from the Gulkana River in Alaska
Epeorus deceptivus (Heptageniidae) Mayfly Nymph from the Gulkana River in Alaska
Epeorus deceptivus (Heptageniidae) Mayfly Nymph from the Gulkana River in Alaska
Ventral view of a Epeorus deceptivus (Heptageniidae) Mayfly Nymph from the Gulkana River in Alaska
Epeorus deceptivus (Heptageniidae) Mayfly Nymph from the Gulkana River in Alaska
Dorsal view of a Epeorus deceptivus (Heptageniidae) Mayfly Nymph from the Gulkana River in Alaska
Ruler view of a Epeorus deceptivus (Heptageniidae) Mayfly Nymph from the Gulkana River in Alaska The smallest ruler marks are 1 mm.

This mayfly was collected from the Gulkana River in Alaska on July 17th, 2011 and added to Troutnut.com by Troutnut on July 20th, 2011.


Start a Discussion of Nymph

References

Epeorus deceptivus Mayfly Nymph Pictures

Collection details
Location: Gulkana River, Alaska
Date: July 17th, 2011
Added to site: July 20th, 2011
Author: Troutnut
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy