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Pteronarcys californica

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

Caddisfly Genus Onocosmoecus (Great Late-Summer Sedges)

The most common species of this genus is Onocosmoecus unicolor.

Where & when

Time of year : Late summer and early fall

Preferred waters: Lakes and slow streams

This genus is nearly as large as Dicosmoecus, but not quite as impressive because its emergence is less concentrated. It can still produce fishable hatches, especially in lakes.

Larva & pupa biology

Diet: Mostly detritus

Current speed: Slow or still

Specimens of the Caddisfly Genus Onocosmoecus

2 Larvae
1 Male Adult
Male Onocosmoecus unicolor (Great Late-Summer Sedge) Caddisfly Adult
I first just assumed this was Dicosmoecus based on anglers' conventional wisdom since it's a large orange "October caddis," but Creno set me straight. I should have keyed it out. After another look under the microscope, it lacks an anepisternal wart on the mesopleuron, which rules out Dicosmoecus. The midtibiae have 2 apical spurs and 1 pre-apical spur, and from there the color pattern of the wing points to Onocosmoecus. The location then narrows the species to unicolor.
2 Adults

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  • LaFontaine, Gary. 1981. Caddisflies. The Lyons Press.
» Genus Onocosmoecus (Great Late-Summer Sedges)
Species in Onocosmoecus
Onocosmoecus unicolorGreat Late-Summer Sedge431
1 species (Onocosmoecus sequoiae) isn't included.
Genus Range
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