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Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana
Salmonflies
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

Dorsal view of a Grammotaulius betteni (Limnephilidae) (Northern Caddisfly) Caddisfly Larva from the Yakima River in Washington
This is a striking caddis larva with an interesting color pattern on the head. Here are some characteristics I was able to see under the microscope, but could not easily expose for a picture:
- 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.
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.
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Stonefly Species Sweltsa occidens (Sallflies)

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.

Source: A Contribution To The Knowledge Of Sweltsa Exquisita (Frison) And Sweltsa Occidens (Frison) And Description Of A New Species Of Sweltsa From The Northern Rocky Mountains, U. Sweltsa A. (Plecoptera: Chloroperlidae)

Male. General color yellow in life, head with dark ocellar rings, pronotum yellow, but with dark lateral margins, black stripe running down terga 1 - 8, terminal mark on tergum 8 longer than wide and never divided. Tergum 9 lacking bare elevated process (Fig. 10). Epiproct erectile, elongate, in dorsal view, tapered to apex (Fig. 10); extreme apex bare, (Figs. 10 - 13), in lateral aspect, apex expanded ventrally, but generally flattened laterally (Figs. 12 & 13); dorsal and lateral surface of epiproct covered with dense pile of long appressed setae, extending to the epiproct base (Figs. 10 - 13), laterally, base bare (Fig. 12). Aedeagus tubular, constricted near upper 1/3, with two bulbous lobes, bearing two smaller apical projections (Figs. 14 & 15), more expanded apex with broad lobes and dorsal finger-like projection medially (Fig. 16), surface with comb-like setae arranged in interrupted rows, with patch of stronger setae located at base of constricted area (Figs. 16 & 17).

Female. Color and markings similar to male. Subgenital plate subtriangular and not covering all of sternum 9, apex more narrowly rounded, often exhibiting a shallow emarginate area at the tip, but the posterior margin is usually entire (Fig. 27) for Sweltsa durfeei.


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References

Stonefly Species Sweltsa occidens (Sallflies)

Taxonomy
Species Range
Common Names
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