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.

Stream photos

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Sweltsa (Sallfly) Stonefly Nymph Sweltsa (Sallfly) Stonefly Nymph

Dorsal view of a Sweltsa (Chloroperlidae) (Sallfly) Stonefly Nymph from the Yakima River in Washington

This species was fairly abundant in a February sample of the upper Yakima.

10 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.

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Caddisfly Family Polycentropodidae

These small caddisflies are of occasional importance, but the family doesn't include any major superhatches.

Where & when

In 1533 records from GBIF, adults of this family have mostly been collected during June (31%), July (27%), August (15%), May (15%), and September (6%).

In 509 records from GBIF, this family has been collected at elevations ranging from 3 to 10663 ft, with an average (median) of 1299 ft.

Family Range

source

Map of specific collection sites

Hatching behavior

The pupae emerge on the surface.

Egg-Laying behavior

Females of this family lay their eggs on the bottom, either by diving down or crawling down objects.

Larva & pupa biology

Diet: Smaller aquatic insects

Current speed: Slow or still

Shelter type: Wide variety of nets and net-like structures

Specimens of the Caddisfly Family Polycentropodidae

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

2 Larvae

Holocentropus Caddisfly Larva

11 Pictures

Dorsal view of a Holocentropus (Polycentropodidae) Caddisfly Larva from the Yakima River in Washington

This one seems to tentatively key to Holocentropus, although I can't make out the anal spines in Couplet 7 of the Key to Genera of Polycentropodidae Larvae nor the dark bands in Couplet 4 of the Key to Genera of Polycentropodidae Larvae, making me wonder if I went wrong somewhere in keying it out. I don't see where that could have happened, though. It might also be that it's a very immature larva and doesn't possess all the identifying characteristics in the key yet. If Holocentropus is correct, then Holocentropus flavus and Holocentropus interruptus are the two likely possibilities based on range, but I was not able to find a description of their larvae.

Collected February 17, 2023 from the Yakima River in Washington

Added by Troutnut on February 20, 2023

Collected February 17, 2023 from the Yakima River in Washington and added by Troutnut on February 20, 2023

Polycentropus (Brown Checkered Summer Sedge) Caddisfly Larva

4 Pictures

Dorsal view of a Polycentropus (Polycentropodidae) (Brown Checkered Summer Sedge) Caddisfly Larva from the Delaware River in New York

Collected May 12, 2007 from the Delaware River in New York

Added by Troutnut on May 18, 2007

Collected May 12, 2007 from the Delaware River in New York and added by Troutnut on May 18, 2007

Discussions of Polycentropodidae

Polycentropodidae or?

14 replies

Posted by LowBudget on Oct 1, 2013

Last reply on Jul 24, 2014 by Crepuscular

The first image is of a live caddis. It was collected from Trout Creek which is in the Delaware River watershed in upstate NY. The background is 1/4 inch ruled graph paper which is under the Petrie dish holding the caddis with water.

The second shows small silk nets found on rocks in the same stream during the same sampling.

I've been working all of my ID books including "Freshwater Macroinvertebrates of Northeastern North America" by Peckarsky.

The upper lip does not seem to have the T shape of a Fingernet caddis. It does have the heavy mandible with a brush of Polycentropodidae.

But, I'm not completely satisfied.

Anyone have thoughts on this?

Ed

Start a Discussion of Polycentropodidae

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.