The Sioux snaketail was recently discovered in Wisconsin, and not much is known about this species. The thorax is green with black shoulder stripes. The legs are mostly black with pale green stripes on thighs. The eyes are blue-gray. The abdomen is black with yellow markings. The average length of the body is about 1.8 inches long. The Sioux snaketail is almost identical to the brook snaketail (Ophiogomphus aspersus), differing by abdominal markings and shape of reproductive appendages. However, the brook snaketail is not found in Wisconsin, being restricted to Appalachian Mountains and northeastern United States. Ophiogomphus species are very similar to each other in some aspects, careful inspection is needed to identify those snaketails.
Found in Wisconsin and Iowa, Sioux snaketail likes rivers and streams that are sand-bottomed. It is only known from a handful of counties in western Wisconsin.
Late May to early July in Wisconsin.