Large, swift-flying dragonflies, usually marked with blue, green or yellow. Adults hunt tirelessly for insects over ponds, lakes and streams, and wander widely in search of prey. Most species rest in a vertical position, but a few sit flat on the ground. Females have a prominent ovipositor and lay eggs in water plants or floating wood above or below the water line. Larvae are slender and sleek, with flat labia lacking bristles; they are rapacious hunters among water plants. Recently, A. californica and A. multicolor have been transferred from Aeshna to Rhionaeschna.
Not usually the predominant species at a locality, except on the south coast, where it can be abundant in some places. Most common in the south, rare in northern B.C. and extremely rare in the Yukon. Lives in peaty lakes, flooded beaver ponds, and sedge and cattail marshes at low and medium elevations.