Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana

Salmonflies
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

Stream photos

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Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva

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.

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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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Mayfly Species Anthopotamus verticis (Golden Drakes)

Where & when

In 38 records from GBIF, adults of this species have mostly been collected during June (55%), July (32%), and August (8%).

In 1 record from GBIF, this species has been collected at elevation of 618 ft.

Species Range

source

Map of specific collection sites

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 Potamanthus diaphanus

Body length: 8-10 mm
Wing length: 9.5 mm

A pale species; wings of male wholly pale, tail joinings not darker; no abdominal markings.

Head and thorax pale yellowish white. Eyes and ocelli black. “Tips of femora, tarsi and tibiae very faintly infuscated, a subapical inferior spot on the fore tibia being more distinct” (Needham). Wings hyaline whitish. Abdomen pale yellowish white, the tergites “with a satiny sheen.” Tails white, joinings not noticeably darker.

According to Argo, the wings of both sexes are wholly pale, and the eyes of the males rather large, separated by a distance not greater than diameter of one eye. The species seems to be distinct from others in the genus.

Start a Discussion of Anthopotamus verticis

References

Caucci, Al and Nastasi, Bob. 2004. Hatches II. The Lyons Press.
Needham, James G., Jay R. Traver, and Yin-Chi Hsu. 1935. The Biology of Mayflies. Comstock Publishing Company, Inc.