Salmonflies
Pteronarcys californica
The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
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As far as I can tell, this species has only previously been reported from one site in Oregon along the Columbia gorge. However, the key characteristics are fairly unmistakable in all except for one minor detail:
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.
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Identification: Key to Species of Agnetina Adults
Identification: Key to Species of Agnetina Adults
Adapted from Stark et al (1986)
| Option 1 | Option 2 |
|---|---|
Femora transversely banded 
| Femora longitudinally banded 
|
Male hemitergal process foot-shaped with long slender ankle and toe 
| Male hemitergal process either with toe blunt or ankle short 
|
Female subgenital plate truncate, dark pigment covers sternum 8 in continuous mesal band 
| Female subgenital plate rounded with areas of basolateral dark pigment 
|
| Remaining species: Agnetina capitata and Agnetina flavescens | |
2 Example Specimens
This stonefly emerged in my aquarium, and unfortunately I severely damaged its wings just trying to catch it. It's still an interesting specimen, especially since I was able to also photograph the nymphal shuck it emerged from. I was surprised by just how light it was shortly after emerging. I photographed it a couple days later when it had darkened considerably; it was a pale, almost pastel yellow at first.
| |
| Agnetina annulipes | Go to Couplet 2 |
Adapted from Stark et al (1986)
The current couplet is highlighted with darker colors and a icon, and couplets leading to this point have a icon.
Couplet 1 (You are here)
Leads to Agnetina annulipes:
- Femora transversely banded
- Male hemitergal process foot-shaped with long slender ankle and toe
- Female subgenital plate truncate, dark pigment covers sternum 8 in continuous mesal band
Leads to Couplet 2:
- Femora longitudinally banded
- Male hemitergal process either with toe blunt or ankle short
- Female subgenital plate rounded with areas of basolateral dark pigment
Couplet 2
Leads to Agnetina capitata:
- Ventral margin of femora dark forming mesal yellow window
- Apical portion of male hemitergal process long and sinuate, toe bluntly rounded
- Dark pirgment areas on female sterna 8 and 9 large quadrangular
Leads to Agnetina flavescens:
- Ventral margin of femora light
- Swollen area of male hemitergal process adjacent to foot obscuring ankle area
- Dark pigment areas of female sterna 8 and 9 not quadrangular
Start a Discussion of this Couplet
References
- Stark, B.P. 1986. The Nearctic Species of Agnetina (Plecoptera: Perlidae). Journal of the Kansas Entomological Society 59(3): 437-445.