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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.

Middle Fork Snoqualmie From the Middle Fork Snoqualmie River in Washington

Stream photos

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Dorsal view of a Doroneuria baumanni (Perlidae) (Golden Stone) Stonefly Nymph from Sears Creek in Washington
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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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Alderfly Genus Sialis

Alderflies are typically mistaken for small hellgrammites as larvae and large caddisflies as adults. They turn up often enough in nymph samples that it's nice to know what they look like. There are rumors of their occasional importance to trout, but the average anglers is not likely to encounter it.

Where & when

Time of year : Early season

In 294 records from GBIF, adults of this genus have mostly been collected during April (35%), May (27%), June (25%), and July (8%).

In 85 records from GBIF, this genus has been collected at elevations ranging from 495 to 11526 ft, with an average (median) of 3182 ft.

Genus Range
Map of specific collection sites

Hatching behavior

Time of day : Evening

Pupae burrow into the ground near to, but not in, the stream. Because the emergence takes place on land it is unimportant to trout.

Egg-Laying behavior

Time of day: Daytime

The mating adults gather over the water in good numbers but do not usually fall into the water unless wind knocks them off course.

They lay their eggs on dry objects near the water. Ernest Schwiebert describes their egg placement in Matching the Hatch:

The egg masses are deposited on rocks, limbs, leaves and bridges where they are over running water and in the sunlight. They are placed so that the hatching larvae fall into the stream.

Larva & pupa biology

Current speed: Slow

Substrate: Silt

The larvae are burrowers like the Ephemeridae mayfly nymphs, digging down into the silt.

Specimens of the Alderfly Genus Sialis

1 Male Adult
Male Sialis hamata Alderfly Adult
2 Pictures
Male Sialis hamata (Sialidae) Alderfly Adult from the Touchet River in Washington
Added by Bnewell on May 18, 2012
Collected May 14, 2012 from the Touchet River in Washington and added by Bnewell on May 18, 2012
4 Larvae

Start a Discussion of Sialis

References

  • Brigham, W.U., A.K. Brigham, and A. Gnilke. 1982. Aquatic Insects and Oligochaetes of North and South Carolina. Midwest Aquatic Entomologist.
  • Schwiebert, Ernest G. 1955. Matching the Hatch. MacMillan Publishing Company.

Alderfly Genus Sialis

Taxonomy
  1. Kingdom Animalia (Animals)
  2. » Phylum Arthropoda (Arthropods)
  3. » Class Insecta (Insects)
  4. » Order Megaloptera (Hellgrammites, Dobsonflies, and Alderflies)
  5. » Family Sialidae (Alderflies)
  6. » Genus Sialis
Species in Sialis
Sialis hamata
1
2
Species in Sialis: Sialis hamata
23 species (Sialis aequalis, Sialis americana, Sialis arvalis, Sialis bilobata, Sialis californica, Sialis concava, Sialis contigua, Sialis cornuta, Sialis dreisbachi, Sialis glabella, Sialis hasta, Sialis infumata, Sialis iola, Sialis itasca, Sialis joppa, Sialis mohri, Sialis nevadensis, Sialis nina, Sialis occidens, Sialis rotunda, Sialis spangleri, Sialis vagans, and Sialis velata) aren't included.
Genus Range
Map of specific collection sites
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