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.

Mount Deborah and Hess Mountains. Two of the greatest peaks of the Alaska Range rise behind the braided, glacial Susitna River. These massive mountains are 35 miles north of where I took this picture.

From the Susitna River in Alaska

Stream photos

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Limnephilus (Summer Flier Sedge) Caddisfly Larva Limnephilus (Summer Flier Sedge) Caddisfly Larva

Case view of a Limnephilus (Limnephilidae) (Summer Flier Sedge) Caddisfly Larva from the Yakima River in Washington

This seems to be a young larva of Limnephilus. Although not clear in the picture, several ventral abdominal segments have chloride epithelia.

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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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Mayfly Species Siphlonurus barbaroides (Gray Drakes)

Where & when

In 16 records from GBIF, adults of this species have been collected during June (63%), July (31%), and August (6%).

In 2 records from GBIF, this species has been collected at elevations of 69 and 194 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.

Male Spinner

Described in Needham et al (1935)

Body length: 10-11 mm
Wing length: 10 mm

A species much resembling Siphlonurus barbarus and Siphlonurus columbianus, but differing in finer details of structure of penes. Thorax and dorsum of abdomen, except for usual pale areas, pitch black. Wings without the brownish tinge present in columbianus. Abdominal sternites paler than tergites. Lateral patches combine with oblique streaks to form lateral triangles. On sternites 1 and 2, these triangles are fused at the median line on the anterior margin, so that most of these segments are dark. Penes differ in details of structure from barbarus and columbianus (see fig. 122).

Start a Discussion of Siphlonurus barbaroides

References

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