This large black dragonfly varies from 2.5 to 3.0 inches in the body length. The abdomen has short yellow spots in separated pairs along its length. The forehead is yellow in males and brown in females with sea-green eyes. The female is similar to the male. The male's abdomen is slightly clubbed while the female ovipositor (appendages at end of the abdomen) extends the length of a segment beyond the abdomen.
Common throughout eastern United States and southeastern Canada, this species is found at clear streams or small rivers in the woods. Sometimes it can be seen foraging miles away from larval habitats. It is fairly common throughout the northern two-thirds of Wisconsin.
Late May to mid-August in Wisconsin.