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.
|Cerci approximately one-third length of median filament (about the length of the abdomen)
|Cerci approximately one-sixth length of median filament (about half the length of the abdomen)
|Distinct pair of medial spines present only on abdominal terga 2–9, with the spine tips blunt
|Distinct pair of medial spines present on abdominal terga 1–9, with the spine tips sharp