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.

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Psychodidae True Fly Larva Psychodidae True Fly Larva

Lateral view of a Psychodidae True Fly Larva from Mystery Creek #308 in Washington

This wild-looking little thing completely puzzled me. At first I was thinking beetle or month larva, until I got a look at the pictures on the computer screen. I made a couple of incorrect guesses before entomologist Greg Courtney pointed me in the right direction with Psychodidae. He suggested a possible genus of Thornburghiella, but could not rule out some other members of the tribe Pericomini.

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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 Campsurus decoloratus (White Flies)

Where & when

In 2 records from GBIF, adults of this species have been collected during June (100%).

Species Range

source

Map of specific collection sites

Identification

Species ID from GBIFthe Global Biodiversity Information Facility

Source: Revision of Campsurus violaceus species group (Ephemeroptera: Polymitarcyidae) with new synonymies and nomina dubia in Campsurus Eaton, 1868

Diagnosis. Campsurus decoloratus can be separated from the other species of the genus by the following combination of characters: 1) pedestals and penes similar to Campsurus violaceus, with pedestals elongate with outer corner slightly projected and penes slender, except that " thumb " is finger-like (figures 22 - 23 of Traver 1947); 2) female socket with straight transverse opening and with an anterior longitudinal rib (Figs. 45 - 46).

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.

Female Spinner

Described in Needham et al (1935)

Body length: 16 mm
Wing length: 14.5 mm

Mesothorax yellowish fuscous; fore legs blackish; abdomen yellowish, with lateral obscure fuscous stripes.

Head brownish-black, antennae pale. Mesothorax yellowish fuscous. Fore legs blackish, middle and hind legs yellowish. Wings hyaline, yellowish; subcosta fuscous, other veins yellowish. Abdomen yellowish, with lateral obscure fuscous stripes. Tails yellowish. (Description taken from Hagen and Eaton). (Description is probably of a female specimen.)

Description from GBIFthe Global Biodiversity Information Facility

Female. Abdominal sternum VIII with a subquadrate single socket on the anteromedian area, the anterior furrow presents a thin medial rib (" r " in Fig. 46); in both female adults studied the groove (socket`s opening) appears obtruded by a subespherical aglutinated material ("? " in Fig. 46). The sternum VIII is completely covered by microtrichiae, except anteriorly and around the groove (Figs. 45 - 46).

Eggs (Fig. 44). Length, 188 - 237; width, 145 - 175. L / W ratio (N = 5): 1.2 - 1.6. Hemispherical to ovate, with convex and concave sides as usual, capped pole broader, cap formed by> 15 very long threads coiled around each other in a single stronger filament, chorionic surface covered by small punctures, except below the polar cap. Micropylar devices unknown.

Start a Discussion of Campsurus decoloratus

References

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