Blue-winged Olives
Baetis
Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.
The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.
Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
Stonefly Species Sierracapnia shepardi (Little Snowflies)
Species Range
Physical description
Most physical descriptions on Troutnut are direct or slightly edited quotes from the original scientific sources describing or updating the species, although there may be errors in copying them to this website. Such descriptions aren't always definitive, because species often turn out to be more variable than the original describers observed. In some cases, only a single specimen was described! However, they are useful starting points.
Description from GBIFthe Global Biodiversity Information Facility
Source: Sierracapnia, A New Genus Of Capniidae (Plecoptera) From Western North America
Male. Tergum 7 knob wide and often divided into right and left lobes, knob width 29 - 32 % of segment 7 width (Figs. 17, 19). Epiproct in dorsal view with nearly uniform width along length, maximum width 17 - 25 % of epiproct length; maximum width occurs near mid epiproct; apex broadly rounded and with median posterior-projecting triangular lobe (Fig. 17 and see Fig. 19 in Nelson and Baumann 1987); dorsal membrane dark gray or black, sometimes lighter at tip. Epiproct in lateral view with pronounced reverse (S-shaped) curve, the dorsal surface concave in anterior half and convex in posterior half; ventral surface deeply curved; maximum depth 18 - 20 % of length; maximum depth occurs anterior of mid epiproct; neck narrow (Fig. 18). Epiproct dorsolateral horns closely appressed to main dorsal surface; horn length 14 - 18 % epiproct length; horn tips extend forward to 80 - 86 % of epiproct length (Figs. 18, 20; Table 1).
Female. Subgenital plate heavily sclerotized and dark; plate covers entire width of sternum 8 from its posterior to anterior edge; subgenital plate often with small lateral notches; sclerotization extends onto sternum 7 (Fig. 247, Nelson and Baumann 1989).
Start a Discussion of Sierracapnia shepardi
Stonefly Species Sierracapnia shepardi (Little Snowflies)
Species Range
Common Names
Resources
- NatureServe
- Integrated Taxonomic Information System
- Global Biodiversity Information Facility
- Described by Nelson, C.R. & Baumann, R.W. (1987) New winter stoneflies of the genus Capnia with notes and an annotated checklist of the Capniidae of California (Plecoptera: Capniidae). Entomography 5, 485–521.