**Caddisfly Genus Arctopsyche (Great Gray Spotted Sedges)**

Mayflies

Caddisflies

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Taxonomic Navigation -?-

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Trichoptera (Caddisflies)

» Family Arctopsychidae

» Genus Arctopsyche (Great Gray Spotted Sedges)

Species in Arctopsyche
Arctopsyche grandisGreat Gray Spotted Sedge	0	0
Arctopsyche irrorataGreat Gray Spotted Sedge	0	0

2 species aren't included.

Common Name

Match	Common Name
	Great Gray Spotted Sedges

Arctopsyche grandis, the western species, is by far the most important in this genus. It produces excellent fishable hatches.

Larva & Pupa Biology

Diet: Smaller insects

Shelter Type: They spin and tend their nets instead of building a case.

The larvae live for two years before emerging and are especially prone to behavioral drift (Behavioral drift: The nymphs and larvae of many aquatic insects sometimes release their grip on the bottom and drift downstream for a while with synchronized timing. This phenomenon increases their vulnerability to trout just like emergence, but it is invisible to the angler above the surface. In many species it occurs daily, most often just after dusk or just before dawn.) at dawn and dusk.

Recent Discussions of Arctopsyche

Arctopsyche grandis 1 Reply »

Posted by Flymonster on Sep 8, 2011 in the species Arctopsyche grandis

Last reply on Sep 8, 2011 by Entoman

Here in the Willamette Valley the McKenzie Caddis (as Arctopsyche grandis is known locally) usually begins its emergence sometime around mid-May and can continue into mid-June. The most emergence activity will be noted on warm days once the water temperature reaches @ 52f. Most hatches occur on warm sunny days from 4pm-7pm. Arlen Thomason goes into great detail about the life-cycle and behaviors of a. grandis in his book "Bug Water".

At least for me, the McKenzie Caddis, marks the beginning of summer and excellent fly fishing for trout on the McKenzie, Middle Fork Willamette, North Fork of the Middle Fork Willamette, and our other local rivers and streams.

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Jargon Defined:

Behavioral drift: The nymphs and larvae of many aquatic insects sometimes release their grip on the bottom and drift downstream for a while with synchronized timing. This phenomenon increases their vulnerability to trout just like emergence, but it is invisible to the angler above the surface. In many species it occurs daily, most often just after dusk or just before dawn.

Larvae: Many classes of aquatic insects, such as caddisflies, midges, craneflies, dobsonflies, alderflies, and many more, are known as "larvae" rather than "nymphs" in their juvenile stages. They have mostly soft bodies rather than hard exoskeletons. These insects also advance through a "pupa" stage before reaching adulthood.

Useful References:

LaFontaine, Gary. 1981. Caddisflies. The Lyons Press.

Schwiebert, Ernest G. 1955. Matching the Hatch. MacMillan Publishing Company.