SeasonalityAdults emerge in early to mid July depending on water temperatures.
IdentificationMales (length = 18 mm) have paraprocts that are flattened, triangular and sharply pointed at their anteriorly directed tips, and have spinules on Tergites 9 and 10. Females (length = 35 mm) have the subgenital plate produced and flattened or emarginate apically. Adults can be distinguished from Acroneuria abnormis by the presence of anal gill remnants and dark brown sclerotization on the head within the ocellar triangle. Nymphs have anal gills, and a banded pattern on abdominal terga with a light M-pattern in front of the anterior ocellus.