The common spreadwing has two forms that are now considered separate species; the northern spreadwing (
Lestes disjunctus) and the larger
southern spreadwing (
Lestes australis). Both forms are difficult to separate from each other, and from the similar
sweetflag spreadwing. The female of the sweetflag spreadwing is readily identified by her extremely long ovipositor. However, the males of the 3 groups can only be separated by subtle differences in the shapes of the terminal appendages, hamular processes, and apical head of the abdomen. The length of a common spreadwing varies from 1.3 to 1.8 inches, depending on gender and subspecies. The male's thorax is dark above with thin greenish shoulder stripes and pale sides. The colors are obscured by pruinosity as the spreadwings age, especially in males. The abdomen is dark above, usually green iridescence, with a gray tip when mature. The female's thorax is black above with thin pale shoulder stripes and gray, tan or yellowish sides. The abdomen is dark iridescent green above and pale brown below.