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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 Ephemerella mucronata (Ephemerellidae) Mayfly Nymph from the Yakima River in Washington
This is an interesting one. Following the keys in Merritt R.W., Cummins, K.W., and Berg, M.B. (2019) and Jacobus et al. (2014), it keys clearly to Ephemerella. Jacobus et al provide a key to species, but some of the characteristics are tricky to interpret without illustrations. If I didn't make any mistakes, this one keys to Ephemerella mucronata, which has not previously been reported any closer to here than Montana and Alberta. The main character seems to fit well: "Abdominal terga with prominent, paired, subparallel, spiculate ridges." Several illustrations or descriptions of this holarctic species from the US and Europe seem to match, including the body length, tarsal claws and denticles, labial palp, and gill shapes. These sources include including Richard Allen's original description of this species in North America under the now-defunct name E. moffatae in Allen RK (1977) and the figures in this description of the species in Italy.
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 Rhyacophilidae (Green Sedges)

See Rhyacophila for details. It is an extremely important trout stream genus, containing well over 100 American species.

The other genus, Himalopsyche, contains only one relatively unimportant American species.

Where & when

In 1217 records from GBIF, adults of this family have mostly been collected during June (24%), July (21%), May (18%), August (17%), September (7%), and April (6%).

In 610 records from GBIF, this family has been collected at elevations ranging from 10 to 23622 ft, with an average (median) of 3652 ft.

Family Range

Identification

To further identify a specimen of Rhyacophilidae to the genus level, use the Key to Genera of Rhyacophilidae Adults.

Specimens of the Caddisfly Family Rhyacophilidae

1 Adult
3 Pupae
9 Larvae

Start a Discussion of Rhyacophilidae

References

Caddisfly Family Rhyacophilidae (Green Sedges)

Taxonomy
Genus in Rhyacophilidae: Himalopsyche, Rhyacophila
Family Range
Common Name
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