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Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large Brown Trout that only touch streamers for the rest of the year.

Mayfly Species Ephoron album (White Fly)

Where & when

This is the only Ephoron species in the West, where it is known from the large rivers near Yellowstone National Park. It is abundant in the Midwest, and it is present in the East but not to the extent of Ephoron leukon.

Physical description

Most of these descriptions are direct 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

Body length: 12 mm
Wing length: 11–12 mm

Vertex of head yellowish brown with purplish markings; mesonotum light yellowish brown; veins of costal margin of fore wing purplish grey, all others pale. Face pale yellowish; second basal joint of antenna dusky at apex, filament whitish. Eyes black. Vertex of head yellowish brown, marked and sometimes almost obscured by purplish shading; darkest between ocelli, which are heavily dark-ringed at base. Pronotum yellowish; pleura with purplish grey streaks above leg base. Mesonotum yellow, tinged with yellowish brown on each side of median area; scutellum pale yellowish. Metanotum yellowish brown. Pleura and sternum pale yellowish, the former often tinged with yellowish brown. Fore femur and tibia purplish; femur marked with yellowish white along ventral edge; ventral edge of tibia whitish at extreme base; tarsus smoky grey at base, becoming silvery white apically. Middle and hind legs pale yellowish white. Wings rather semi-hyaline, with faint purplish tinge along the costal border. Longitudinal and cross veins of costal margin purplish grey, cross veins somewhat darker than longitudinals; as far back as the anterior branch of media, the cross veins are faintly greyish; all other veins of both wings colorless. Abdomen pale yellowish white, basal and middle segments often semi-hyaline; apical tergites yellowish. Genitalia pale (see fig. 78). Tails pale smoky at base, becoming whitish apically; joinings opaque whitish.

Recent Discussions of Ephoron album

Polymitarcyidae Question
1 replies
Posted by Steamntrout on Jun 22, 2017
Last reply on Jun 23, 2017 by Crepuscular
What size are these nymphs & Sub Imago's?

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