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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.

Lateral view of a Onocosmoecus (Limnephilidae) (Great Late-Summer Sedge) Caddisfly Larva from the Yakima River in Washington
This specimen keys pretty easily to Onocosmoecus, and it closely resembles a specimen from Alaska which caddis expert Dave Ruiter recognized as this genus. As with that specimen, the only species in the genus documented in this area is Onocosmoecus unicolor, but Dave suggested for that specimen that there might be multiple not-yet-distinguished species under the unicolor umbrella and it would be best to stick with the genus-level ID. I'm doing the same for 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.

Mayfly Species Procloeon rufostrigatum (Tiny Sulphur Duns)

Where & when

Time of year : June through October; peaks in July and August

In 10 records from GBIF, adults of this species have been collected during July (30%), August (30%), September (20%), and June (20%).

In 3 records from GBIF, this species has been collected at elevations of 2270, 2854, and 29016 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 Centroptilum rufostrigatum
Body length: 4.5-5 mm
Wing length: 5 mm

Abdominal tergites of male imago pale yellowish white, each with a row of four minute red transverse dashes on the posterior margin on each side.

Face and thorax deep blackish brown. Thoracic sternum deep black brown; posterior margin of mesonotum and pleural sutures tinged with pale yellowish brown. Legs pale yellowish white. Wings hyaline. Hind wing long and narrow, two longitudinal veins (see fig. 165). Abdominal segments 2-6 pale yellowish white; each tergite with a lateral row of four minute red transverse dashes on each side, these dashes situated on the posterior margin of the tergite. Tergites 7-10 deep chocolate brown, sternites alabaster white; the pleural fold forms a sharp division between these two colors. A faint slightly curved hair-line of black marks the spiracular area, on the pale segments. Forceps and tails white. Inner margin of second joint of the forceps with a poorly developed inward bulge, much less apparent than in C. caliginosum (now a synonym of Procloeon caliginosum) (see fig. 166).

From the allied C. caliginosum, this species may be separated by the smaller size, and the lesser development of the bulge on the second forceps joint. The much narrower hind wing distinguishes it from C. bifurcatum (now a synonym of Anafroptilum bifurcatum).

Start a Discussion of Procloeon rufostrigatum


Mayfly Species Procloeon rufostrigatum (Tiny Sulphur Duns)

Species Range
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