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.

Stream photos

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Tricorythodes (Trico) Mayfly Nymph Tricorythodes (Trico) Mayfly Nymph

Dorsal view of a Tricorythodes (Leptohyphidae) (Trico) Mayfly Nymph from Mystery Creek #308 in Washington

9 Recently Added Photos

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 Genus Nyctiophylax (Dinky Light Summer Sedges)

Where & when

In 208 records from GBIF, adults of this genus have mostly been collected during June (37%), July (33%), May (14%), and August (13%).

In 76 records from GBIF, this genus has been collected at elevations ranging from 7 to 7201 ft, with an average (median) of 1841 ft.

Genus Range

source

Map of specific collection sites

Hatching behavior

Time of day : Slow water

The pupae take a long time to break through the film.

Egg-Laying behavior

Females lay their eggs underwater, either by diving through the surface or crawling down streamside rocks and twigs.

Larva & pupa biology

Current speed: Slow

Shelter type: Unusual retreat; see notes

These caddisflies build unusual homes, which Gary LaFontaine describes in detail in Caddisflies:

The small, yellow-and-brown larvae of this genus builds a chamberlike retreat, open at both ends, over a hollow in a stick or rock. It leaves loose threads over each opening and when a smaller animal touches the retreat, disturbing the threads, this eight- to ten-millimeter carnivore rushes out and seizes its prey.

Specimens of the Caddisfly Genus Nyctiophylax

1 Adult

Nyctiophylax affinis (Dinky Light Summer Sedge) Caddisfly Adult

12 Pictures

Nyctiophylax affinis (Polycentropodidae) (Dinky Light Summer Sedge) Caddisfly Adult from the Teal River in Wisconsin

This specimen is certainly Nyctiophylax and most likely Nyctiophylax affinis. I don't know my caddisfly parts well enough to definitively follow the Nyctiophylax key in Morse (1972), but that source states that affinis is the predominant Midwestern species, being widespread and common in the region where I found this one. The anatomy of this one seems to match those at least as well as the other two potential options based on range, Nyctiophylax uncus and Nyctiophylax banksi.

Collected June 7, 2021 from the Teal River in Wisconsin

Added by Troutnut on June 9, 2021

Collected June 7, 2021 from the Teal River in Wisconsin and added by Troutnut on June 9, 2021

Start a Discussion of Nyctiophylax

References

LaFontaine, Gary. 1981. Caddisflies. The Lyons Press.
Morse, JC. 1972. The genus Nyctiophylax in North America. Journal of the Kansas Entomological Society 42(2): 172-181.
Swisher, Doug and Carl Richards. 2000. Selective Trout. The Lyons Press.