British Insects: the Odonata
Ruddy Darter Dragonfly.
Adults. Adults about 31–34–37 mm long (the sexes similar in length). Average wingspan 55 mm; hindwings 24–29 mm long.
The eyes dorsally narrowly apposed to dorsally broadly contiguous; brown (in the female), or red (in the male).
Legs black. Thoracic antehumeral stripes absent. The wings spread more or less horizontally in repose; dissimilar in shape and venation; sessile; suffused with colour at their bases only. The tinting amber (or saffron). The inner wing venation blackish. Discoidal cell divided longitudinally into a conspicuous triangle and supra-triangle. Antenodal veins in the forewings 6–8 (fewer in the hindwings). Pterostigma well over twice but no more than five times as long as wide; deep red (with black edging, in the male), or reddish brown (in the female).
Abdomen linear from a conspicuously swollen base, or swollen both basally and distally and markedly constricted in between (scarcely constricted in the female, markedly so forward of the middle in the male); 21–26 mm long; predominantly red (in the male), or green, or yellow (olive-yellow, in the female); plain (apart from median black dashes on segments 8 and 9 of both sexes, which are characteristic of the genus and particularly prominent in this species.); without mid-dorsal spots. The male abdomen without auricles on segment 2; with a single inferior anal appendage.
Nymphs. The nymphs stout, the body expanded in the middle; when mature, 15–17 mm long.
The head in dorsal view markedly narrowing from immediately behind the eyes. The postocular lobes curving sharply to the back of the head from some distance behind the eyes. The antennae 7 segmented. The mask having the prementum hollowed dorsally; without a median cleft. The prementum bearing 24–28 major setae (12+12 to 14+14). The body of the labial palps bearing 9–11 major setae. Legs longer than the abdomen.
The abdomen terminating in five short spine-like appendages. The cerci no more than hald the length of the paraprocts. The abdomen with mid-dorsal spines. The mid-dorsal abdominal spines prominent on segments 5 to 8. The gizzard with 4–8 folds.
Distribution. Northern England, English Midlands, East Anglia, Wales, southeast England, southwest England, Isle of Wight, Ireland, and central southern England (but always local in the north of England, and very few recent records from there). Adults on the wing late June to late September (generally in best mature condition through July and August).
Classification. Anisoptera; family Libellulidae.
Illustrations. • Sympetrum sanguineum and S. scoticum (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’.