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
Some characteristics from the microscope images for the tentative species id: The postero-lateral projections are found only on segment 9, not segment 8. Based on the key in Jacobus et al. (2014), it appears to key to Neoleptophlebia adoptiva or Neoleptophlebia heteronea, same as this specimen with pretty different abdominal markings. However, distinguishing between those calls for comparing the lengths of the second and third segment of the labial palp, and this one (like the other one) only seems to have two segments. So I'm stuck on them both. It's likely that the fact that they're immature nymphs stymies identification in some important way.
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 Suwallia (Sallflies)
Only Suwallia pallidula is known to be commonly encountered on trout streams.
Genus Range
Specimens of the Stonefly Genus Suwallia
2 Female Adults
I didn't key this one out under the microscope, but I just keyed a similar one from Montana and this one matches the macroscopic appearance closely enough that I'm guessing it's the same thing.
I collected a few of these throughout the afternoon. The positive ID on the adults allowed me to also put a species ID on the nymphs.
2 Adults
A large number of photos from the microscope allowed a fairly confident ID on this one, which not coincidentally matches very well a previous specimen of Suwallia pallidula that I collected in Washington.
2 Nymphs
This specimen keys out to Suwallia, for which I did not find any nymph species keys. However, I'm placing it in Suwallia pallidula because I caught a few adults in the same spot that closely resembled the abundant nymphs and keyed them out to species. Features I noted under the microscope when keying this specimen to genus included apical hairs of cercal segments that were directed at posterior angles, and the longest apical hairs of distal segments were shorter than their following segment.
Start a Discussion of Suwallia
References
- Jacobus, L. M., Wiersema, N.A., and Webb, J.M. 2014. Identification of Far Northern and Western North American Mayfly Larvae (Insecta: Ephemeroptera), North of Mexico; Version 2. Joint Aquatic Science meeting, Portland, OR. Unpublished workshop manual. 1-176.
Stonefly Genus Suwallia (Sallflies)
Taxonomy
Species in Suwallia
Suwallia forcipataForceps Sallflies
0
0
Suwallia pallidulaLittle Yellow Stoneflies
5
35
Species in Suwallia: Suwallia forcipata, Suwallia pallidula
6 species (Suwallia autumna, Suwallia dubia, Suwallia lineosa, Suwallia marginata, Suwallia sierra, and Suwallia wardi) aren't included.