|scientific name Acroneuria lycorias (Newman)|
Large, cool water streams and rivers.
Adults emerge in early to mid July depending on water temperatures.
Males (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.
The life cycle is three years in Saskatchewan, and the nymphal habitat is under larger rocks in regions of the stream with the swiftest current.
The species is not endangered, but as with all stoneflies, it is sensitive to organic pollution.
Nymphs are carnivorous, preying on other smaller aquatic insect nymphs and larvae.
In Alberta, the species is known from boreal streams. In North America, it occurs from northern Quebec south through New England to Florida and west to Ontario, Manitoba, Saskatchewan, and Tennessee.
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