Header image
Enter a name
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.

Dorsal view of a Setvena wahkeena (Perlodidae) (Wahkeena Springfly) Stonefly Nymph from Mystery Creek #199 in Washington
As far as I can tell, this species has only previously been reported from one site in Oregon along the Columbia gorge. However, the key characteristics are fairly unmistakable in all except for one minor detail:
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.
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.
Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Caddisfly Species Amiocentrus aspilus (Little Western Weedy Water Sedges)

This species produces fishable hatches across the West.

I encountered them in mid-August on the Henry's Fork, mating in thick swarms up and down the bank of the Harriman Ranch reach. However, millions of Tricorythodes mayflies found their way onto the water that same morning and it's unclear if the trout were seeing and responding to the caddisflies at all.

Where & when

Time of year : March to October; LaFontaine reports peaks in late June and in September

Preferred waters: Best in spring creeks

In 23 records from GBIF, adults of this species have mostly been collected during July (35%), August (30%), May (13%), June (9%), and March (9%).

In 4 records from GBIF, this species has been collected at elevations of 6060, 6250, 6726, and 7005 ft.

Species Range

Larva & pupa biology

Substrate: Vegetation

Larvae of this species are especially prone to behavioral drift early in the season.

Specimens of the Caddisfly Species Amiocentrus aspilus

1 Adult

Start a Discussion of Amiocentrus aspilus

References

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

Caddisfly Species Amiocentrus aspilus (Little Western Weedy Water Sedges)

Taxonomy
Species Range
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy