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.

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Neoleptophlebia Mayfly Nymph Neoleptophlebia Mayfly Nymph

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.

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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 Allocapnia virginiana (Little Snowflies)

Species Range

source

Identification

Species ID from GBIFthe Global Biodiversity Information Facility

Source: Larvae Of The Winter Stonefly Genus Allocapnia (Plecoptera: Capniidae) In Mississippi, Usa

Diagnosis. Among the other species whose larvae display erect or semi-erect bristles at midlength of most abdominal terga (Allocapnia granulata, Allocapnia rickeri, Allocapnia starki) the larvae of Allocapnia virginiana are distinguished from Allocapnia rickeri by virtue of a straight dorsal margin of developing male tergum 10 (Fig. 31), and from the others in having the posterolateral aspect of this structure slanted rather than truncate.

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: The Winter Stoneflies (Plecoptera: Capniidae) Of Mississippi

Male epiproct. Epiproct dorsal limb usually apically truncate, and bearing a prominent, suture in apical half of limb (Fig. 46); apical section of limb bears numerous fine anastomosed grooves and ridges covering apical half (Fig. 48); basally the wide, apical, ridged section is separated from smooth and narrowed base by a pair of lateral concavities (Figs. 46 - 47). Lower limb slightly wider than upper limb for most of length and bearing subapical notches.

Female subgenital plate. Abdominal sterna 7 and 8 separated by membrane, or sometimes poorly fused by faint sclerite. Subgenital plate broadly arcuate and usually projecting slightly beyond posterolateral margins of sternum 8 (Figs. 51, 65). Source: New Records Of Winter Stoneflies (Plecoptera: Capniidae) In Mississippi

Start a Discussion of Allocapnia virginiana

References

Jacobus, L. M., Wiersema, N.A., and Webb, J.M. 2014. Identification of Far Northern and Western North American Mayfly Larvae (Insecta: Ephemeroptera), North of Mexico; Version 2. Joint Aquatic Science meeting, Portland, OR. Unpublished workshop manual. 1-176.