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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.

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.

Stonefly Species Calineuria californica (Golden Stones)

Calineuria californica is the largest western species of the Perlidae family, with female adults approaching 40 mm in some locales. This species is perhaps better known by anglers under its former scientific name, Acroneuria californica. It is the primary Golden Stonefly hatch of the West Coast states, a role shared by Hesperoperla pacifica to a lesser degree. Their roles are reversed in the Rocky Mountain states where pacifica takes the top billing. Both are now commonly known as Golden Stones as regional colloquial differences have slowly dissipated. They were both commonly called Brown Willowflies in the Rockies and Golden Stones in the coastal states, which explains the confusion caused by references in older fly fishing literature.

This large stonefly is ubiquitous in western freestones and can provide incredible angling at ther height of their activity. On rivers lacking populations of Pteronarcys californica, they are the largest and most significant hatch of the year. They are generally a late spring/early summer emerger. They crawl out of the water to perch on streamside riparian foliage or rocks where they shed their nymphal shucks. They also mate in the same locations. The females end up back on the water in good numbers and offer good dry fly fishing. But it is the nymphs that offer the best angling opportunities, especially as they stage in the shallows in preparation for emergence.

The nymphs lack anal gills which easily separates them from Hesperoperla and Claassenia. Their lateral ocelli (simple eyes) in a pale background separates them from Doroneuria.

The male adults of Calineuria and Hesperoperla are easy to tell apart by looking at their hammers. Both are quadrangular but Calineuria is longer than wide. The heads and pronotums of both sexes are dramatically marked in Calineuria while Hesperoperla is more plain.

Where & when

Time of year : Late Spring, early Summer

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.

Source: Eggs Of Western Nearctic Acroneuriinae (Plecoptera: Perlidae)

Egg. Outline oval with short stalked collar, ends broadly rounded (Fig. 1). Length including collar ca. 430 - 460 µm, equatorial width ca. 360 - 390 µm, collar length ca. 35 - 40 µm, collar width at mid-length ca. 60 - 68 µm. Egg body at base of collar encircled by slightly raised ridge. Sides of collar with irregular, prominent struts (Fig. 2); rim flanged and irregularly incised (Figs. 1 - 2). Anchor biscuit-shaped, surface with scattered mushroom bodies (Fig. 3). Chorionic surface relatively smooth but with obscure hexagonal follicle cell impressions visible at 500 X (Figs. 2, 4). Micropylar row subequatorial.

Specimens of the Stonefly Species Calineuria californica

1 Male Adult
2 Female Adults
3 Nymphs

1 Streamside Picture of Calineuria californica Stoneflies:


Start a Discussion of Calineuria californica

References

Stonefly Species Calineuria californica (Golden Stones)

Taxonomy
Species Range
Resources
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