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Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana
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 Limnephilidae (Giant Sedges) Caddisfly Larva from the Yakima River in Washington
This specimen resembled several others of around the same size and perhaps the same species, which were pretty common in my February sample from the upper Yakima. Unfortunately, I misplaced the specimen before I could get it under a microscope for a definitive ID.
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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Mayfly Species Paraleptophlebia moerens

Where & when

In 13 records from GBIF, adults of this species have been collected during June (69%), May (15%), July (8%), and April (8%).

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.

Male Spinner

Body length: 6 mm
Wing length: 6 mm

This is another small, clear-winged species with whitish, cross-lined abdomen. Head and thorax dark brown above. Legs pale. Wings whitish with a milky stigmatic area covering costal and subcostal interspaces. Costal cross veins almost wholly obsolete even in the stigmatic area where their faint vestiges are numerous, simple, and considerably aslant.

Abdomen brown on the ends; segments whitish on 3 to 6; less so on 2 and 7. The dorsal apical cross-bands of the white segments are well marked, as are also the lateral, longitudinal, spiracular lines which meet them at the hind angle of the segments. Forceps with a large basal lobe-like dilatation of its first segment. Penes separated for half their length by an oval notch, the aperture of which is closed by a lobe-like prolongation inward of their distal ends. Outer angle of the tips broadly rounded. The proximal portion of its margin is prolonged forward in an incurved spine; attached to this spine is the usual reflexed spur which is very slender (see fig. 133). Tails white.

Start a Discussion of Paraleptophlebia moerens


  • Needham, James G., Jay R. Traver, and Yin-Chi Hsu. 1935. The Biology of Mayflies. Comstock Publishing Company, Inc.

Mayfly Species Paraleptophlebia moerens

Species Range
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