Both genders of the subarctic bluet are readily identified by the wide blue shoulder stripes that are usually divided, forming a blue rectangle and square. There are additional distinctive black markings on the side and underneath of the thorax and on the 2nd abdominal segment. The body length of the subarctic bluet varies from 1.1 to 1.3 inches for both genders. The male is pale blue with black markings. The male is similar to the taiga bluet but with more black markings. The thorax has black stripes and the abdomen has black rings with a blue tip. Sometimes, the abdomen is greenish in the middle. The female is duller than the male. The female differs from the taiga bluet female by having tan streaks on the sides of the abdomen.
Found in northern US and Canada, this species prefers open fens, bogs, and marshes especially those with sphagnum moss. In Wisconsin, where we are at the southern limit of its range, it is known from just a few scattered sites.
Throughout its range, the flight season is from early June to mid-August.