The Blue Dasher is a dragonfly of the skimmer family. Mature males develop a bluish-white pruinescence on the back of the abdomen and, in western individuals, on the thorax. They display this to other males as a threat while defending territories at the edge of the water. Females are recognized by the narrow yellow parallel stripes on the abdomen. Both sexes have an amber patch at the base of each hindwing. Males develop a sky-blue (or Carolina-blue) abdomen when they approach maturity.