Species of the genus Libellula (king skimmers) often perch on shoreline vegetation, are stout bodied, and usually have distinctive body and wing patterns.
This skimmer acquired its name from the marks on the wings. There are twelve black spots, three per a wing, and eight white spots, two per a wing. The brownish male has a white abdomen. The brown female has yellow stripes down the abdomen with faded white marks on the wings. Twelve-spotted skimmers are large and strong flyers. The length of the body varies from 2.0 to 2.2 inches.
This species is common throughout United States and southern Canada. It is usually found at ponds, marshy-bordered lakes, bogs, and slow streams. It is widely distributed throughout Wisconsin.
Late May to early September in Wisconsin.