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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.

Dorsal view of a Neoleptophlebia (Leptophlebiidae) Mayfly Nymph from the Yakima River in Washington
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.
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 exquisita (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 black ocellar rings, pronotum yellow except for wide black lateral margins, abdomen with wide black stripe covering terga 1 to 8, black mark on tergum 8 much broader than long as shown in Frison (1935) and sometimes even slightly divided medially. Tergum 9 with a definite, bare elevated transverse process on the anterior margin (Figs. 2 & 3). The anterior margin of the process varies from entire to slightly emarginate (Figs. 2 & 3). In dorsal aspect, the epiproct is erectile, elongate, and subparallel (Fig. 4); in lateral view, slightly enlarged subapically (Figs. 6 & 7), in dorsal aspect, apex sharp and bare (Fig. 5), laterally, rounded and bare at edge (Figs. 6 & 7); in dorsal aspect, epiproct surface covered with dense pile of appressed long setae, extending to base (Figs. 4 - 7), in lateral aspect, 2/3 or more of epiproct, covered by pile-like hairs, ventrally bare (Fig. 6). Aedeagus tubular basally, dorsal aspect subtriangular, with two small dorsal lobes, bearing long thin setae (Fig. 8), lateral, terminal aspect exhibiting paired curled hornlike lobes (Fig. 9); surface with pores (Fig. 9).

Female. Color and dark markings similar to male. Subgenital plate large, nearly covering sternum 9, sides subparallel, with a broadly rounded apex, that can sometimes appear truncate (Fig. 26).


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References

Stonefly Species Sweltsa exquisita (Sallflies)

Taxonomy
Species Range
Common Names
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