This is a very large and unmistakable species in a monotypic genus – one of the largest dragonflies in the United States!
This huge, dark brown species has green thoracic stripes, and exceedingly narrow, green abdominal rings. Males have striking blue eyes. Distinguish from large mosaic darners with green on abdomen by presence of very narrow rings on the abdomen of swamp darner, not spots as on mosaic darners, and by the very large size of swamp darner. Cyrano darner is most similar to swamp darner in our area, but Cyrano has much more green on the abdomen and has a noticeably projecting forehead that swamp darner lacks.
This species is common throughout the eastern United States and southeastern Canada. Preferred habitats are shallow, shaded woodland ponds, including those that are sometimes temporary; also some swamps and slow streams. In Wisconsin, it is widespread but local and rarely common at a given site. The population here may be partially migratory. Likely does not coexist well with centrarchid fishes (primarily sunfishes [genus Lepomis] and black basses [genus Micropterus]).
The flight season is from early June to early September in northern part of its range, but the chances of seeing a swamp darner are best in spring and early summer.