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.
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.
A large species of the brunnea group, having basal lateral spines on penes.
Clypeus dull grey, “crossed by a black band at its base” (McD.). Head ochreous at bases of antennae and around ocelli. Thorax deep brown. Anterior to the wing roots a pale ochreous patch, within which are two blackish streaks. Pleural sutures and bases of wings with ochreous markings. Fore leg blackish. Middle and hind legs golden brown; a black streak on basal half of each femur; tarsi blackish. Wings hyaline; stigmatic area tinged with pale amber. Venation blackish-brown. Abdominal segments deep reddish brown; lateral and posterior margins of tergites narrowly light yellow, so that abdomen appears annulate. Posterior sternites darker in color, the posterior margins yellow-banded as on the dorsum. Forceps deep brown. Tails blackish. Penes distinctly outcurved at tip, each bearing a series of very small spines near apex and on lateral margin. A large spine laterally at base on outer margin (see fig. 100).
The annulate abdomen, large size and genitalic structures should serve to distinguish this from other allied species.