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October Caddisflies

Scientific Name
MatchScientific Name
**Dicosmoecus

This common name refers to only one genus.

Caddisfly Genus Dicosmoecus

These are sometimes called October Caddisflies.
This is a superhatch in the West. Gary LaFontaine had a self-proclaimed obsession with Dicosmoecus, and he devotes several pages of Caddisflies to stressing the importance of its larvae, pupae, and adults. He wrote:

The question for fly fishermen seeking big trout is: "Which insects provide the best opportunity for catching such fish?" My list would be: Giant Orange Sedge (Dicosmoecus sp.), Salmon Fly (Pteronarcys californica, a stonefly), and the Michigan Mayfly (Hexagenia limbata). Dicosmoecus is the most important -- and the contest is not even close.

His reasons for this judgement are five traits of Dicosmoecus:

  • Very large size: Adults 30mm long, and thick.

  • Activity concentrated within 2-3 weeks.

  • Emerges in the low, clear water of fall.

  • Active during afternoon and evening.

  • Abundant in rivers with sea-run trout.


I have never fished the West to experience Dicosmoecus, but I have enough experience with Hexagenia limbata to know that a greater insect must be truly amazing.
Dicosmoecus gilvipes (Giant Orange Sedge) Caddisfly NymphDicosmoecus gilvipes (Giant Orange Sedge) Caddisfly Nymph View 3 Pictures
Collected October 5, 2010 from in
Added to Troutnut.com by on June 27, 2011
Female Dicosmoecus atripes (Giant Orange Sedge) Caddisfly AdultFemale Dicosmoecus atripes (Giant Orange Sedge) Caddisfly Adult View 6 PicturesThis specimen is 26 mm.
- Entoman
Collected September 27, 2013 from in
Added to Troutnut.com by on September 29, 2013
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