British Insects: the Odonata
Brilliant Emerald Dragonfly.
Adults. Adults about 39–53–57 mm long (the female slightly the longer). Average wingspan 78 mm; hindwings 34–36 mm long.
The eyes dorsally narrowly apposed to dorsally broadly contiguous; green (in both sexes).
Legs black. Thoracic antehumeral stripes absent. The wings spread more or less horizontally in repose; dissimilar in shape and venation; sessile; colour tinted throughout (more strongly towards their bases). The tinting amber. The inner wing venation blackish. Discoidal cell divided longitudinally into a conspicuous triangle and supra-triangle. Antenodal veins in the forewings about 7–10 (fewer in the hindwings); without distinct primaries, and those in the costal and subcostal spaces more or less aligned. Pterostigma well over twice but no more than five times as long as wide (in the female somewhat longer in the hindwings than in the forewings); dark brown.
Abdomen robustly linear from a conspicuously swollen base (in the female), or swollen both basally and distally and markedly constricted in between (in the male, the constriction involving several segments forward of the middle); 37–40 mm long; predominantly green to bronze; metallic; plain; without mid-dorsal spots. The male abdomen auriculate on segment 2; with a single inferior anal appendage.
Nymphs. The nymphs stout, the body expanded in the middle; when mature, 24–25 mm long.
The antennae 7 segmented. The mask having the prementum hollowed dorsally; without a median cleft. The prementum bearing 22–24 major setae (11+11 to 12+12). The body of the labial palps bearing 6–7 major setae. Distal margins of the labial palps strongly crenate. Legs longer than the abdomen.
The abdomen terminating in five short spine-like appendages. The cerci more than half the length of the paraprocts. The abdomen with mid-dorsal spines. The mid-dorsal abdominal spines prominent on segments 4 to 9 (these recurved, and sometimes with a vestigial one on segment 3). The gizzard with 4–8 folds.
Distribution. Northern Scotland and southeast England. Adults on the wing early June to late August (generally in best mature condition late June to early August).
Classification. Anisoptera; family Corduliidae.
Illustrations. • Somatochlora arctica and S. metallica (from Lucas).
To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. British insects: Dragonglies and Damselflies (Odonata). Version: 1st January 2012. http://delta-intkey.com’.