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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 Pycnopsyche guttifera (Limnephilidae) (Great Autumn Brown Sedge) Caddisfly Larva from the Yakima River in Washington
This specimen appears to be of the same species as this one collected in the same spot two months earlier. The identification of both is tentative. This one suffered some physical damage before being photographed, too, so the colors aren't totally natural. I was mostly photographing it to test out some new camera setting idea, which worked really well for a couple of closeups.
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.

Mayfly Species Labiobaetis dardanus

Where & when

In 4 records from GBIF, adults of this species have been collected during July (50%), June (25%), and October (25%).

In 49 records from GBIF, this species has been collected at elevations ranging from 335 to 7644 ft, with an average (median) of 4741 ft.

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

Described in Needham et al (1935) as Baetis dardanus
Body length: 5 mm
Wing length: 5.5 mm

Abdominal tergites 2-6 of male imago hyaline whitish; genitalia of the modified moffati type (now a synonym of Baetis tricaudatus); costal projection of hind wing entirely wanting; hind wing two-veined.

Turbinate eyes are slightly larger than in B. pygmaeus (now a synonym of Acerpenna pygmaea). Thorax dark shiny blackish brown, the lateral sutures marked with whitish. Legs pale yellowish. Wings hyaline. No costal projection near the base of the hind wing. Only two veins present in the hind wing. Abdominal segments 2-6 hyaline whitish; tergites 7-10 brownish olive, the sternites opaque white with brown shading. Faint ruddy shading along the pleural fold. Forceps whitish.

Start a Discussion of Labiobaetis dardanus


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

Mayfly Species Labiobaetis dardanus

Species Range
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