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

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

Artistic view of a Perlodidae (Springflies and Yellow Stones) Stonefly Nymph from the Yakima River in Washington
This one seems to lead to Couplet 35 of the Key to Genera of Perlodidae Nymphs and the genus Isoperla, but I'm skeptical that's correct based on the general look. I need to get it under the microscope to review several choices in the key, and it'll probably end up a different Perlodidae.
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 Species Spinadis simplex

Species 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

Described in Needham et al (1935) as Anepeorus simplex
Body length: 6-8 mm
Wing length: 7.5-9.5 mm

A yellowish white species, as opposed to the general brown coloration of Anepeorus rusticus.

Head yellowish; eyes of living insect bright greenish yellow above and below; ocelli black-ringed at base. Thoracic notum flesh-colored; remainder of thorax yellow with distinct pinkish tinge. Legs white; femora yellowish; apex of fore tibia and tarsal joinings, and the “extreme tips of all the tarsi” (Walsh) brownish. Wings hyaline; all veins fine except cross veins in apical portion of costal space, which are coarse. Cross veins in basal portion of costal space very fine, indistinct, lacking in basal 1/5 of space, except for humeral cross vein. Veins in apical two-thirds of fore wing brownish; all others hyaline (Walsh says, all costal cross veins occasionally brownish). Abdominal segments 2-7 hyaline whitish, immaculate; segments 8-10 opaque, yellowish; in our Georgia specimen, tergites distinctly tinged with rose, especially on posterior margins of 9 and 10. Genitalia yellowish. Lateral apical portion of penes with two large and one smaller lobe on each side. Tails white, dusky at tips. Genitalia as in fig. 112.

The general pale coloration of this species distinguishes it at once from A. rusticus, the only other species thus far known in the genus.

Start a Discussion of Spinadis simplex


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

Mayfly Species Spinadis simplex

Species Range
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy