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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.

Dorsal view of a Limnephilidae (Giant Sedges) Caddisfly Larva from the Yakima River in Washington
This specimen resembled several others of around the same size and perhaps the same species, which were pretty common in my February sample from the upper Yakima. Unfortunately, I misplaced the specimen before I could get it under a microscope for a definitive ID.
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.

Mayfly Genus Pentagenia

Where & when

In 70 records from GBIF, adults of this genus have mostly been collected during June (39%), July (21%), August (20%), September (10%), and May (6%).

In 10 records from GBIF, this genus has been collected at elevations ranging from 823 to 6247 ft, with an average (median) of 3576 ft.

Genus Range

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.

Male Spinner

Wing length: 14–15 mm

Rather large mayflies, wing 14 to 15 mm. in length; a broad dark band dorsally on abdomen. Eyes of male quite large, approximated apically. Posterior margin of head of female almost straight between the eyes. Fore leg of male very short relatively, only slightly longer than head and thorax combined. Fore tibia 114 to 114 times as long as femur; tarsus slightly longer than femur. Basal tarsal joint short; second subequal to fifth; third and fourth progressively shorter. Hind leg very similar to fore leg; distal tarsal joint about as long as the three preceding joints together. Proportions of joints of leg of female much as in hind leg of male. Wings very much asin Hexagenia, except that the cells in the costal angulation of the hind wing may be divided by a cross line into two series. Penes simple, rod-like, divergent apically, united only at base. Subanal plate of female with a V-shaped median notch on apical margin; a short projection at each outer corner, directed outward and backward. Tails three in both sexes, middle one very short.

Wings and genitalia of the imago are figured by Eaton, Needham and Spieth; the two last mentioned also give nymphal structures.

Nymph

Frontal process on head of nymph bifid. Mandibular tusks relatively stout, crenate on outer (upper) margin. Maxillary palp very stout, 3-jointed; second and third joints fringed with long hairs. Galea-lacinia wide, somewhat conical. Labial palp 2-jointed; distal joint long, clavate, covered densely with long hairs; several long spines near tip (fig. 83).


Start a Discussion of Pentagenia

References

  • Needham, James G., Jay R. Traver, and Yin-Chi Hsu. 1935. The Biology of Mayflies. Comstock Publishing Company, Inc.

Mayfly Genus Pentagenia

Genus Range
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