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Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin
Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.

Artistic view of a Perlodidae (Springflies and Yellow Stones) Stonefly Nymph from the Yakima River in Washington
This one seems to lead to Couplet 35 of the Key to Genera of Perlodidae Nymphs and the genus Isoperla, but I'm skeptical that's correct based on the general look. I need to get it under the microscope to review several choices in the key, and it'll probably end up a different Perlodidae.
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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Caddisfly Genus Psychoglypha (Snow Sedges)

These caddisflies may be important to the winter angler because they are one of the only insects around. Gary LaFontaine relays an interesting correspondence about this genus in Caddisflies:

Dr. George Roemhild explained to me how he finds these winter caddisflies in February and March: "They crawl up on the snowbanks, but when the sun hits their dark wings they melt down out of sight. That's how I collect them, by walking along looking for holes in the snow."

I will keep an eye out this winter and hopefully collect some specimens to photograph.

Where & when

In 117 records from GBIF, adults of this genus have mostly been collected during October (18%), April (15%), May (14%), September (11%), March (11%), November (9%), June (5%), and December (5%).

In 50 records from GBIF, this genus has been collected at elevations ranging from 34 to 11499 ft, with an average (median) of 5719 ft.

Genus Range

Hatching behavior

Time of day : Warmest part of the day

Habitat: Warm shallows

On bright winter days when the trout move into the shallows to sun themselves, these caddisflies may pick the same destination to emerge and the trout will feed.

Larva & pupa biology

Diet: Leaf matter, algae, dead animals

The larvae are the most important stage of Psychoglypha. They are especially prone to behavioral drift and, unlike most species, they do it during the daytime.

Specimens of the Caddisfly Genus Psychoglypha

1 Male Adult
1 Female Adult

Start a Discussion of Psychoglypha


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

Caddisfly Genus Psychoglypha (Snow Sedges)

12 species (Psychoglypha avigo, Psychoglypha bellus, Psychoglypha browni, Psychoglypha klamathi, Psychoglypha leechi, Psychoglypha mazamae, Psychoglypha ormiae, Psychoglypha pritus, Psychoglypha rossi, Psychoglypha schmidi, Psychoglypha schuhi, and Psychoglypha smithi) aren't included.
Genus Range
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