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Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York
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.

Lateral view of a Female Sweltsa borealis (Chloroperlidae) (Boreal Sallfly) Stonefly Adult from Harris Creek in Washington
I was not fishing, but happened to be at an unrelated social event on a hill above this tiny creek (which I never even saw) when this stonefly flew by me. I assume it came from there. Some key characteristics are tricky to follow, but process of elimination ultimately led me to Sweltsa borealis. It is reassuringly similar to this specimen posted by Bob Newell years ago. It is also so strikingly similar to this nymph from the same river system that I'm comfortable identifying that nymph from this adult. I was especially pleased with the closeup photo of four mites parasitizing this one.
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.
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 Species Remenus kirchneri (Blue Ridge Springflies)

Species Range

Identification

Source: Holomorphology And Systematics Of The Eastern Nearctic Stonefly Genus Remenus Ricker (Plecoptera: Perlodidae)

Diagnosis. Males of Remenus kirchneri are morphologically similar Remenus daniellae. Males possess a tongue-shaped epiproct in dorsal aspect, which is widest medially or near the basal ¼ and is dorsoventrally flattened. Whereas the epiproct of Remenus daniellae is clavate, is widest towards the apical ¼ and narrows posteriorly both in dorsal and lateral aspects. Additionally, the epiproct of Remenus daniellae typically possesses a short translucent tube at the apex, which Remenus kirchneri lacks. Furthermore, Remenus kirchneri generally has sensilla basiconica on tergum 9 and consistently has 12 – 20 sensilla basiconica on each hemitergal lobe. In contrast, Remenus daniellae generally lacks sensilla basiconica on tergum 9 and has <4 minute sensilla basiconica on each hemitergal lobe.

Females of Remenus kirchneri are most similar to Remenus daniellae. Separation of these species may require associated males. Generally, the subgenital plate of Remenus kirchneri is parallel sided basally, whereas in Remenus daniellae, the subgenital plate is typically convergent.

Mature larvae of Remenus kirchneri are separable from the other sympatric species, Remenus bilobatus, by the lack of long setae on the basal cercal segments. Remenus duffieldi also lacks long setae on the basal cercal segments, but it does not occur east of the French Broad River (Fig. 115).

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: Holomorphology And Systematics Of The Eastern Nearctic Stonefly Genus Remenus Ricker (Plecoptera: Perlodidae)

(Figs. 1, 92 – 113) http: // lsid. speciesfile. org / urn: lsid: Plecoptera. speciesfile. org: TaxonName: 606Source: Holomorphology And Systematics Of The Eastern Nearctic Stonefly Genus Remenus Ricker (Plecoptera: Perlodidae)

Male. (Fig. 92). Macropterous; forewing length, 9.1 – 10.5 mm (n = 10) (Fig. 93). Body length, 8.2 – 10.2 mm (n = 10). General body color yellow-gold with light brown markings. Dorsum of head typical of genus (Fig. 94). Pronotum light brown, covered in regularly spaced setae, with pale, glabrous rugosities mediolaterally (Fig. 94); medial pale area slightly wider posteriorly (Fig. 94). Abdominal terga yellow-gold with darkened anterior margins; rarely with darkened lateral margins. Tergum 9 with or without mediolateral patches of 3 – 5 sensilla basiconica (Fig. 95). Hemitergal lobes short, not separated from 10 th tergum, with long trichoid sensilla and 12 – 20 sensilla basiconica on each lobe (Figs. 95 – 97). Epiproct length ~ 270 – 500 µm; width ~ 20 – 59 µm (n = 3); epiproct dorsoventrally flattened, tongue-shaped and lightly sclerotized (Figs. 95 - 96, 98 – 100); covered in dense, thick hair-like spinulae (Fig. 100); when produced forward, exceeding the anterior margin of the basal sclerite. Paragenital plates triangular (Figs. 95, 98). Basal cowl covered in dense lightly pigmented spinulae (Figs. 95 – 96).

Female. Macropterous; forewing length 10.0 – 11.9 mm (n = 10). Body length, 9.2 – 12.6 mm (n = 10). General color and morphology similar to the male. Abdominal terga pale, without darkened anterior or lateral margins. Subgenital plate broadly rounded (Fig. 101 – 102), occasionally with a shallow posteromedial emargination (Fig. 102), or broadly triangular (Fig. 103); lightly sclerotized, with regularly spaced setae, extending 1/2 – 4/5 over sternum 9; posterolateral margins convex; basolateral margins typically parallel; basolateral crease typically curved, concave posteriorly, extending ~ 1/4 length anteriorly into sternum 8 (Figs. 101 – 103).

Ovum. Shape typical of genus (Figs. 104 – 107). Length 438 – 460 µm; width 348 – 353 µm.

Larva. (Fig. 108). Body length 8.5 – 11.4 mm, (n = 10). Head (Fig. 109), lacinia (Fig. 110), mandibles (Fig. 111), and pronotum (Fig. 109) typical of genus. Mature male larva with a short terminal process (developing epiproct) with a constriction at the basal 1/3; apical 2/3 tapering to a narrowly rounded apex (Fig. 112). Basal cercal segments with whorls of short setae (Fig. 113).


Start a Discussion of Remenus kirchneri

Stonefly Species Remenus kirchneri (Blue Ridge Springflies)

Taxonomy
Species Range
Common Name
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