Striped Emeralds (Somatochlora)
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The twenty six native Somatochlora species, better known as Striped Emeralds, get their name from the many species with thoracic stripes.
Differentiating among Somatochlora species requires a look at the thorax color, noting the absence or presence of stripes, along with the presence or absence of white rings around the otherwise dark abdomen.
No identification is perfect because of documented instances of Somatochlora hybridizing in areas where species overlap.
The top picture shows a male Ringed Emerald (Somatochlora albicincta). It inhabits the northern areas of North America such as the Pacific Northwest, north to Alaska. It can also be found in New England.
Like many of the Mosaic darner species (genus Aeshna), striped emeralds (genus Somatachlora) can be identified by the side thoracic pattern.
From a side view, the Mountain Emerald (Somatochlora semicirularis) usually can be identified by two yellow markings on the side of the metallic green thorax.
While the second picture does not capture a good side view of the thorax, it does show two light spots on the segment directly below the thorax, which are indicative of the female.
The picture also displays an eye color closer to blue, rather than green, with the eye color change an artifact of the lighting angle.
Mountain emeralds inhabit lake and bog areas of the mountainous West, from Alaska in the north to California in the south, and east to areas of the Rocky Mountains of Colorado.
Due largely to the extreme climactic conditions of their alpine and subalpine existence, naiads take several years to develop.
© 2006-2011 Patricia A. Michaels