Wisconsin Odonata Survey

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Somatochlora ensigera  Martin, 1906
Plains Emerald


Corduliidae, Emerald Family
"Most Wanted" Species

The medium-sized, dark brown striped emeralds have some pale markings on the thorax and abdomen, black legs, clear wings and brilliant green eyes. The thorax has a metallic bronze-green sheen and the abdomen is dark metallic black-green. Most species are uncommonly seen, but this may be largely due to their secretive nature. When flying, most species look alike which is why in-hand identifications of their anatomical features are often needed.

Status-Global/State:

Global: G4     Wisconsin: S2S3    

Distinguishing Characteristics:

This emerald varies from 1.9 to 2.0 inches in the length. The thorax has two bright lateral stripes on each side. The abdomen has few markings except near the end of the abdomen for the males. Females have yellow lateral stripes along most of the abdomen. The face is yellow. The female ovipositor is a short perpendicular spout.

Description of Habitat/Range:

Found in northern mid United States, especially northern Great Plains, the plains emerald prefers small prairie or woodland streams and ditches. This species is known in Wisconsin from just a few eastern counties.

Flight Season:

Throughout its range, the typical flight season is from mid-June to mid-August.


Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
40%
(2)
60%
(3)
Shading illustrates monthly percentages of the total flight season records for the species. Each flight season record is a unique date/location/observer combination where one or more adult or an exuvia was recorded (excludes nymphs). The actual number of flight season records for each month is shown in parentheses.

Flight seasons begin earlier in the southern part of the state, often by a week or more. Also, flight charts may not be accurate for rare species because of few data available.
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Photo of Female plains emerald
Female plains emerald. © Ilka Milne

Female plains emerald



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