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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.

Case view of a Pycnopsyche guttifera (Limnephilidae) (Great Autumn Brown Sedge) Caddisfly Larva from the Yakima River in Washington
It's only barely visible in one of my pictures, but I confirmed under the microscope that this one has a prosternal horn and the antennae are mid-way between the eyes and front of the head capsule.

I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.

The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.

Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
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 Callibaetis fluctuans (Speckled Duns)

This uncommon species may be locally abundant.

Where & when

In 24 records from GBIF, adults of this species have mostly been collected during August (38%), July (29%), September (17%), and June (13%).

In 20 records from GBIF, this species has been collected at elevations ranging from 325 to 7306 ft, with an average (median) of 3337 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.

Female Spinner

Body length: 6-7 mm
Wing length: 6.5-8 mm

A brownish white species; cross veins of fore wing relatively few in number; marginal intercalaries single; wing of male not pigmented.

Head and thorax brownish white; vertex of female sometimes ferruginous, “with a double longitudinal carina.” Antennal filament dusky, sometimes pale at the base, a double light brown band on the thoracic notum, confluent behind. Legs whitish, the tips of the tarsi cloudy. Wings hyaline, iridescent; veins rather coarse near the base; longitudinal veins generally brown, and occasionally edged with brown toward the base. Cross veins fine, always hyaline. In the wing of the female, the space between costa and subcosta is hyaline; on the costal margin are 15 to 18 small brown spots, some of these confluent. A light brown band is present behind the subcosta, containing about 14 round hyaline spots—“some of them confluent before or behind with the hyaline part of the wing.” Posterior margin of this brown vitta variable, irregular; sometimes with 6 or 7 “large obtuse teeth.” Marginal intercalaries occur singly. Cross veins behind the vitta relatively few in number (14 to 18, according to Walsh).

Abdomen, both tergites and sternites, generally brownish-white, sometimes varied with brown. Two of Walsh’s specimens were pale brown, the 6th segment brown. Tails whitish. (Original description, of female only). The wing of the male (if we are correct in the identification of this species) is unpigmented. In both sexes, brown submedian curved marks are present on tergites and sternites.

Start a Discussion of Callibaetis fluctuans


Mayfly Species Callibaetis fluctuans (Speckled Duns)

Species Range
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