One of the most common darners in Wisconsin and a member of the "blue" or "mosaic" darner group. (1) Moderately-deep notch or "scoop" out of the anterior thoracic stripe (seems to be shaped like a "J" or shallow "V" to me), and (2) no black crossline on face. Male is most similar to Lake Darner (A. eremita). Female is very similar to Green-Striped Darner (A. verticalis).