Wisconsin Odonata Survey title graphic Wisconsin Odonata Survey graphic Wisconsin Odonata Survey graphic Wisconsin Odonata Survey graphic Wisconsin Odonata Survey graphic

Enallagma anna
River Bluet

Williamson, 1900
Coenagrionidae, Pond Damsel Family
"Most Wanted" Species
photo of Male river bluet
Male river bluet — Dan Jackson
The bluets form a group of about 17 similar species in Wisconsin in which the males usually share the characteristics of having blue and black stripes on the thorax, and blue and black markings on the abdomen. In-hand examinations are usually needed to identify them, although they can be grouped into subcategories based on the amount of black showing on the abdomen. Males are easily identified, under magnification, by the shape of their terminal appendages. Females are generally duller than males, and they are more difficult to identify, which is accomplished by subtle differences in the shape of the mesostigmal plates on the top of the thorax. Generally, males are bright blue while the females are green or yellow-green or blue. There are some species that are yellow-orange, a mix of various colors, or black with some blue.
Status-Global/State:
Global: G5 Wisconsin: S3S4
Distinguishing Characteristics:
The male of this species falls into the category of intermediate-type bluets, which have roughly equal amounts of blue and black on the abdomen. The length of the body varies from 1.2 to 1.4 inches. The female is either pale tan or pale blue with black markings like the male. The legs are less heavily marked with black.
Description of Habitat/Range:
Ranging from central to western United States, this species can be found at slow creeks, streams and rivers, often associated with outflow of warm springs. It has been found at a handful of sites in central and southern Wisconsin.
Flight Season:
Throughout out its range, the flight season is from mid-May to early September. In Wisconsin, the peak of the flight season is late June to late July.
(Click on photos to enlarge)
photo of Male river bluet
Male river bluet — Dan Jackson
photo of Male river bluet
Male river bluet — Dan Jackson
photo of Male river bluet
Male river bluet — Dan Jackson
photo of Close-up of male river bluet thorax
Close-up of male river bluet thorax — Dan Jackson
photo of Side (top image) and top view of cercus for male river bluet
Side (top image) and top view of cercus for male river bluet — Dan Jackson
photo of Female river bluet
Female river bluet — Dan Jackson
photo of Female river bluet
Female river bluet — Dennis Paulson
photo of Close-up of female river bluet thorax
Close-up of female river bluet thorax — Dan Jackson
photo of River bluet pair
River bluet pair — Dan Jackson
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