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Enallagma vesperum
Vesper Bluet

Calvert, 1919
Coenagrionidae, Pond Damsel Family
photo of Male vesper bluet
Male vesper 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: S4
Distinguishing Characteristics:
Varying from 1.1 to 1.5 inches in the length, this species is well known for its yellow coloration. The male is yellow with broad black mid-dorsal stripe and thin black shoulder stripes. The abdomen is mostly black above except for some blue near the tip. The female is similar but duller yellow or light green. Her abdomen is mostly black above with a pale tip.
Description of Habitat/Range:
This species ranges throughout eastern United States and southeastern Canada. They can be found at ponds and lakes and slow streams with emergent and aquatic vegetation, mainly in late afternoon to evening (dusk).
Flight Season:
The flight season extends from late May to early September in Wisconsin.
(Click on photos to enlarge)
photo of Male vesper bluet
Male vesper bluet — Dan Jackson
photo of Male vesper bluet with wide thoracic stripe variation
Male vesper bluet with wide thoracic stripe variation — Dan Jackson
photo of Male vesper bluet abdomen tip showing cercus (upper part of clasper) in side view
Male vesper bluet abdomen tip showing cercus (upper part of clasper) in side view — Dan Jackson
photo of Female vesper bluet
Female vesper bluet — Dan Jackson
photo of Immature female vesper bluet
Immature female vesper bluet — Dan Jackson
photo of Close-up of female vesper bluet thorax
Close-up of female vesper bluet thorax — Dan Jackson
photo of Vesper bluet pair
Vesper bluet pair — Dan Jackson
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