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.
Featured on the forum
As far as I can tell, this species has only previously been reported from one site in Oregon along the Columbia gorge. However, the key characteristics are fairly unmistakable in all except for one minor detail:
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.
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.
Stonefly Genus Doroneuria (Golden Stones)
This less common western genus currently has only two species. Doroneuria theodora & Doroneuria baumanni (mostly coastal)
Calineuria and Doroneuria nymphs both lack anal gills and can be confused, but Doroneuria has a ridge of fine hairs running down the center of its body dorsally and is not as dramatically marked. The adults often have very short wings and also lack the striking head markings of Calineuria. The adult males have large quadrangular hammers that are almost twice as long as wide.
Calineuria and Doroneuria nymphs both lack anal gills and can be confused, but Doroneuria has a ridge of fine hairs running down the center of its body dorsally and is not as dramatically marked. The adults often have very short wings and also lack the striking head markings of Calineuria. The adult males have large quadrangular hammers that are almost twice as long as wide.
Genus Range
Identification
To determine whether a specimen of Perlidae belongs to Doroneuria, use the Key to Genera of Perlidae Nymphs.
Specimens of the Stonefly Genus Doroneuria
1 Male Adult
I found this stonefly on some streamside vegetation. I didn't see any in the air in several hours of fishing.
2 Nymphs
I'm not aware of any way to tell the two species of Doroneuria apart as nymphs, so this one is classified to species based on location alone. Doroneuria baumanni is found in the Cascades and in Washington, and the other species is not known here yet.
Start a Discussion of Doroneuria
Stonefly Genus Doroneuria (Golden Stones)
Taxonomy
Species in Doroneuria: Doroneuria baumanni, Doroneuria theodora