Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York

Blue-winged Olives
Baetis

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

The "Fountain Flats" stretch of the Firehole was fishable in the morning after an uncharacteristically cold August night.

From the Firehole River in Wyoming

Stream photos

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Tricorythodes (Trico) Mayfly Nymph Tricorythodes (Trico) Mayfly Nymph

Dorsal view of a Tricorythodes (Leptohyphidae) (Trico) Mayfly Nymph from Mystery Creek #308 in Washington

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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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Caddisfly Species Arctopsyche irrorata (Great Gray Spotted Sedges)

Where & when

In 7 records from GBIF, adults of this species have been collected during May (43%), June (29%), July (14%), and April (14%).

In 10 records from GBIF, this species has been collected at elevations ranging from 1319 to 4209 ft, with an average (median) of 2546 ft.

Species Range

source

Map of specific collection sites

Identification

Species ID from GBIFthe Global Biodiversity Information Facility

Source: Description of the female of Parapsyche cardis Ross (Hydropsychidae: Arctopsychinae) and a revised key to the genera of Hydropsychidae (Trichoptera: Annulipalpia) of the southeastern United States, using wing characters

Diagnosis. The hind wing crossveins sc-r and r-rs are not coincident in their insertion on R, the insertions being separated by at least the length of crossvein r-rs. The female genitalia lack paired sclerotized projections internally.

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: Description of the female of Parapsyche cardis Ross (Hydropsychidae: Arctopsychinae) and a revised key to the genera of Hydropsychidae (Trichoptera: Annulipalpia) of the southeastern United States, using wing characters

Description. Wings (Figs. 17, 28): fwl = 16.5 – 20.5 mm; ? = 1.16 (N = 21). Fore-wings sub-hyaline, infuscate with mottling of yellow spots, shape typical for subfamily. Hind wings uniformly lightly infuscate, immaculate. Female genitalia (Figs. 19 – 20): In cleared specimens in lateral view (Fig. 19), abdominal segment IX anteriorly with strongly sloping lateral margins forming acute angle of approximately 45 with ventral sclerites; convex dorsum half as long as height of segment IX; in caudal view (Fig. 20), dorsum convex. Prominent articulation ventrolaterally between segment IX and segment X, with segments IX and X strongly sclerotized. Segment IX posteroventrolaterally with pair of small sclerotized ridges (sr), each bearing row of setae. In ventrocaudal view of cleared genitalia, horseshoe-shaped sclerite present in dorsal membrane of segment X, located medially between dorsal processes (dp) of segment X. Cleared specimens internally and ventrally with weakly to moderately sclerotized curtain of membrane projecting anterad.