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.
- 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.
Stonefly Species Doroneuria theodora (Golden Stones)
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: Eggs Of Western Nearctic Acroneuriinae (Plecoptera: Perlidae)
Egg. Outline oval with short, narrow collar (Fig. 13). Egg length ca. 530 µm, equatorial width ca. 400 µm, collar length ca. 30 µm , width ca. 60 µm. Chorionic surface coarsely punctate in a band ca. 325 µm wide, extending from near collar (Figs. 14, 16) to smooth opercular band surrounding lid. Lid with obscure, irregularly shaped follicle cell impressions, but punctations absent (Fig.). Micropylar row located on lid; orifices raised, canals obscure (Fig. 15).
Start a Discussion of Doroneuria theodora
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.
Stonefly Species Doroneuria theodora (Golden Stones)
Species Range
Common Names
Resources
- NatureServe
- Integrated Taxonomic Information System
- Global Biodiversity Information Facility
- Described by Needham, J.G. & Claassen, P.W. (1922) The North American species of the genus Acroneuria (Order Plecoptera). The Canadian Entomologist 54, 249–255.