|scientific name Claassenia sabulosa |
Larger, coolwater streams and rivers.
Adults emerge in late June to mid-July.
Males (length = 19.6 mm) are brachypterous, but females (length = 31.4 mm) are long-winged. Males have genital hooks darkly sclerotized at their tips and arising from lateral angles of Tergum 10. Males also have a raised knob or "hammer" on Sternum 9. The female subgenital plate is broadly rounded, usually with a shallow median recession and is little produced over Sternum 9. The subgenital plate has a row of spinules along its posterior margin. Nymphs have anal gills and an occipital ridge composed of spinules.
The life cycle is three years in Saskatchewan, and the nymphal habitat is under stones in swift riffle areas. Adults are nocturnal, emerging at nightfall and when active at dusk or night have the ability to move on the surface of the water somewhat like water-striders. Mating can occur as soon as the female emerges from its nymphal exuvium.
The species is not endangered, but as with all stoneflies, it is sensitive to organic pollution.
Nymphs are carnivorous, feeding on mayfly nymphs, black fly and chironomid larvae.
In Alberta, this species is known from the Saskatchewan River system, and from boreal and mountain streams. In North America, it ranges from the Cordilleran region of British Columbia and Alberta through the Cascade and Rocky Mountains to New Mexico and east to northern Manitoba and northern Ontario.
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