The last larval instar is described and illustrated from material collected in central and southeast Wisconsin, United States, and the larval habitat is described. The larva differs from related species in the arctica group of Somatochlora in having a greater head width and in the dorsolateral setal patterns on abdominal tergites Vl-IX. Segment IX has distinct paired dorsolateral tufts, and VIII, VII, and VI have progressively less defined to absent paired tufts. These characters distinguish the species from the most similar species. S. forcipata, and all others of the arctica group.