Header image
Enter a name
Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York
Blue-winged Olives
Baetis

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

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.

American Grannoms

This common name refers to only one species. Click its scientific name to learn more.

Caddisfly Species Brachycentrus americanus

These are pretty much always called American Grannoms.
Female Brachycentrus americanus (Brachycentridae) (American Grannom) Caddisfly Adult from the Fall River in California
Size 11 mm. Prior to this photo the specimen dropped its large egg mass that was a very dark (almost black) olive sphere almost twice the diameter of the abdomen. Notice the abdomen visible through the wings is both thickened and shortened post egg drop.
Case view of a Brachycentrus americanus (Brachycentridae) (American Grannom) Caddisfly Larva from the Yakima River in Washington
This species of Brachycentrus was extremely common in mid-September kick net samples in the Yakima canyon.

American Grannoms

Scientific Name
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy