E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Somatochlora walshii
Brush-Tipped Emerald
Family: Corduliidae
Species account author: Robert Cannings.
Extracted from Introducing the Dragonflies of British Columbia and the Yukon (2002)

© Robert A. Cannings  Email the photographer   (Photo ID #1048)

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Distribution of Somatochlora walshii in British Columbia.
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Source: (for the static map) RBCM and BCCDC 2004 ©
Details about map content are available here.

Species Information


Description

The side of the thorax has two pale marks, a short stripe at the front and an oval spot behind. The short, dark abdomen has small yellow spots on the sides of segments 5 to 7, at least. Male’s appendages shown in figure. Female’s vulvar lamina is dark; shape shown in figure. Length: ♂ 44 mm, ♀ 47 mm.


Flight Period

B.C., late June to mid September.

Genus Description


The scientific name comes from two Greek words: soma, meaning “body”, and khloros, meaning “green”. The English name refers to the yellow or white markings on the sides of the metallic green or bronzy thorax, but most of the distinctly striped species live in eastern North America; western species have spots, short bars or no marks at all. They all have brilliant green eyes. Most North American species are boreal and Appalachian; 13 of 26 occur in our region. Most live around northern or mountain lakes and peatlands.

Species can be hard to identify, especially the females. Look for pale marks on the side of the thorax and white rings between the segments of the abdomen. Hudsonian, Ringed and Lake emeralds have narrow, white abdominal rings. Examine the shapes of the male’s upper appendages and the female’s vulvar lamina. And look for a brown spot at the base of the hindwings – not the membranule, which can also be dark, but an additional spot (Delicate, Muskeg and Whitehouse’s emeralds have it).

Biology

Family Description

Medium-sized dragonflies most often seen around lakes, boggy streams and peatlands in the mountains or in the north. Of 16 species in our region, 13 have Northern or Beringian ranges. The eyes, often brilliant green, meet broadly on top of the head. The shape of the anal loop in the hindwing is distinctive. Adults seldom perch during feeding and males frequently hover when patrolling for mates; when resting, they normally hang vertically or obliquely from vegetation. In flight, a male frequently arches its abdomen, which is often narrower at the base and tip. Larvae are usually squat and rather hairy; they sprawl in the mud and detritus in the bottom of the waters where they live.
Field Notes

Uncommon. Breeds in sedge meadows or fens, typically with small slow streams flowing through them.

Distribution


Northern. Throughout the southern two-thirds of B.C. to at least 56°N.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
COSEWIC
NativeS4YellowNot Listed
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Photo Sources

General References


Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2019. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 22/11/2019 4:04:11 AM]
Disclaimer: The information contained in an E-Fauna BC atlas pages is derived from expert sources as cited (with permission) in each section. This information is scientifically based.  E-Fauna BC also acts as a portal to other sites via deep links.  As always, users should refer to the original sources for complete information.  E-Fauna BC is not responsible for the accuracy or completeness of the original information.


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