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.

I like this one. Glacial river, taiga, tundra, and the perpetual ice cover of a massive high ridge dozens of miles away in the Wrangell Mountains.

From the Copper River in Alaska

Stream photos

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Zapada cinctipes (Tiny Winter Black) Stonefly Nymph Zapada cinctipes (Tiny Winter Black) Stonefly Nymph

Dorsal view of a Zapada cinctipes (Nemouridae) (Tiny Winter Black) Stonefly Nymph from the Yakima River in Washington

Nymphs of this species were fairly common in late-winter kick net samples from the upper Yakima River. Although I could not find a key to species of Zapada nymphs, a revision of the Nemouridae family by Baumann (1975) includes the following helpful sentence: "2 cervical gills on each side of midline, 1 arising inside and 1 outside of lateral cervical sclerites, usually single and elongate, sometimes constricted but with 3 or 4 branches arising beyond gill base in Zapada cinctipes." This specimen clearly has the branches and is within the range of that species.

13 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 Species Leucotrichia pictipes (Ring Horn Microcaddisflies)

Where & when

Time of year : Late spring and summer

This species is abundant across the northern United States. It can be extremely abundant -- Gary LaFontaine tells in Caddisflies of a population estimate putting this species at 5,000 per square foot in parts of the Madison River. If have found it very abundant in the Midwest as well, though probably not quite to that extreme. You can see this in my underwater photos.

In 33 records from GBIF, adults of this species have mostly been collected during June (42%), July (27%), August (15%), and May (12%).

In 24 records from GBIF, this species has been collected at elevations ranging from 308 to 6726 ft, with an average (median) of 3412 ft.

Species Range

source

Map of specific collection sites

Hatching behavior

Time of day : Any time

Egg-Laying behavior

LaFontaine describes the unique egg-laying behavior of this species in Caddisflies:

[W]hen the females return to lay their eggs and crawl down the backside of the rocks, so many slip into the currents that trout stack up behind midstream obstructions.

Larva & pupa biology

Current speed: Fast

Identification

Species ID from GBIFthe Global Biodiversity Information Facility

Source: A revision of the Neotropical caddisfly genus Leucotrichia Mosely, 1934 (Hydroptilidae, Leucotrichiinae)

Diagnosis. Leucotrichia pictipes is similar to Leucotrichia fairchildi, Leucotrichia imitator, and Leucotrichia sarita. Leucotrichia pictipes bears patches of scales, both on the dorsum of the head and the eversible membranous lobe beneath the posterolateral wart, which are absent in all 3 of the other species. The genitalia of Leucotrichia pictipes are similar to that Leucotrichia imitator, in having multiple membranous lobes arising from the apex of the phallus. While Leucotrichia imitator has 3 lobes, Leucotrichia pictipes can be distinguished by having 2 sets of symmetrically arranged lobes.

Physical description

Most physical descriptions on Troutnut are direct or slightly edited quotes from the original scientific sources describing or updating the species, although there may be errors in copying them to this website. Such descriptions aren't always definitive, because species often turn out to be more variable than the original describers observed. In some cases, only a single specimen was described! However, they are useful starting points.

Description from GBIFthe Global Biodiversity Information Facility

Source: A revision of the Neotropical caddisfly genus Leucotrichia Mosely, 1934 (Hydroptilidae, Leucotrichiinae)

Description. Male. Length of forewing 2.5 - 4.0 (n = 88). Head with patches of scales dorsally; posterolateral warts large, eversible, with scaled membranous lobes revealed when everted, with 2 ocelli; antennae with scape slightly enlarged, pedicel subtriangular, basal 3 flagellomeres narrow and compact. Dorsum of head brown with yellow setae; thorax brown with yellow setae dorsally, brown ventrally; leg segments with brown setae. Forewings covered with fine brown setae with transverse stripe of yellow setae on basal 1/2 and small scattered patches of yellow setae on distal 1/3. Genitalia. Abdominal sternum VII with mesoventral process replaced by tuft of dense, prominent setae. Sternum VIII in ventral view with posterior margin concave. Segment IX anterolateral margin convex, posterolateral margin convex; in dorsal view anterior margin concave, posterior margin broadly concave. Tergum x with dorsal sclerite slender; ventral sclerite semi-elliptic with tridentate posterior margin; membranous apex not well developed. Subgenital plate with dorsal arm not apparent; ventral arm hollow, apex acute (Fig. 34 A), in ventral view base with crenulate margin, apex rounded. Inferior appendage digitate, bearing single dorsal spine; in ventral view apex rounded. Phallus apex bearing U-shaped internal apodeme, broad ventral sclerite, and 2 pairs of membranous apicodorsal lobes.

2 Underwater Pictures of Leucotrichia pictipes Caddisflies:

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The white blotches on this rock are Leucotrichia caddisfly cases, and the wispy tubes are cases made by a type of midge.

In this picture: Mayfly Species Ephemerella invaria (Sulphur), True Fly Family Chironomidae (Midge), and Caddisfly Species Leucotrichia pictipes (Ring Horn Microcaddis).

Taken March 23, 2004

Added by Troutnut on January 25, 2006

Taken March 23, 2004 and added by Troutnut on January 25, 2006

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There's a stonefly nymph in the bottom right corner of this picture, but what's really interesting is those white blotches. They're pretty common in my Wisconsin home river river, stuck flat onto the rocks--lots of rocks have a speckled look as a result. They are microcaddis cases, made by larvae of the caddisfly family Hydroptilidae. These are made by larvae of the subfamily Leucotrichiinae, most likely the genus Leucotrichia. They spin little flat oval cases of silk tight and immobile against the rocks.

In this picture: Caddisfly Species Leucotrichia pictipes (Ring Horn Microcaddis).

Taken March 19, 2004

Added by Troutnut on January 25, 2006

Taken March 19, 2004 and added by Troutnut on January 25, 2006