Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana

Salmonflies
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

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Ephemerella mucronata Mayfly Nymph Ephemerella mucronata Mayfly Nymph

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.

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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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Stonefly Species Haploperla brevis (Sallflies)

Where & when

In 72 records from GBIF, adults of this species have mostly been collected during May (35%), June (33%), July (13%), April (10%), and August (7%).

In 18 records from GBIF, this species has been collected at elevations ranging from 49 to 4663 ft, with an average (median) of 2342 ft.

Species Range

source

Map of specific collection sites

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.

Adult

Described in Banks (1895) as Choraperla brevis

6 mm. Greenish yellow. Head a little broader than thorax, antenna with basal third yellowish beyond black. Prothorax with a fuscous stripe on each side margin, once and one-half as long as broad, barely broader in front, angles rounded, scarcely rugose; tarsi slightly fuscous. Wings nearly hyaline, with greenish veins, crossveins at end of discal cells disjointed, the upper fork of radial sector is not as long as the pedicel beyond these crossveins (in one specimen it is just as long), three crossveins between vein Cu₁ and vein Cu₂.

Start a Discussion of Haploperla brevis

References

Allen RK. 1977. New species of Ephemerella (Ephemerella) from Alberta (Ephemeroptera: Ephemerellidae). The Pan-Pacific Entomologist 53: 286-286.
Banks, N. 1895. New Neuropteroid Insects. Transactions of the American Entomological Society 22(3): 313-316.
Jacobus, L. M., Wiersema, N.A., and Webb, J.M. 2014. Identification of Far Northern and Western North American Mayfly Larvae (Insecta: Ephemeroptera), North of Mexico; Version 2. Joint Aquatic Science meeting, Portland, OR. Unpublished workshop manual. 1-176.
Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.