British Insects: the Odonata
Common Darter Dragonfly.
Adults. Adults about 33–37–41 mm long (the female scarcely shorter than the male). Average wingspan 58 mm; hindwings 26–29 mm long.
The eyes dorsally narrowly apposed to dorsally broadly contiguous; brown, or red (or reddish brown). The narrow black band at the base of the frons not continued down the inner sides of the eyes.
Legs black and yellow (black below and yellow above, the tarsi black). Thoracic antehumeral stripes present to absent (if detectable, less conspicuous than in some other dragonflies); brown (somewhat paler against the brown thorax). The wings spread more or less horizontally in repose; dissimilar in shape and venation; sessile; very briefly suffused with colour at their bases only. The tinting amber (or saffron). The inner wing venation (reddish-) brown. 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; reddish brown, or red (ruddy, and black edged).
Abdomen linear from a conspicuously swollen base (in the female), or swollen both basally and distally and markedly constricted in between (constricted forward of the middle, in the male); 25–30 mm long; predominantly crimson red (in the male), or green, or yellow (olive-yellow, in the female); plain, or predominantly transversely banded, or complexly patterned (apart from median black dashes on segments 8 and 9 of both sexes, which are characteristic of the genus, males have lateral yellow spots on segments 2 and 3, and narrow yellow bands between the segments); 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, 15.5–18 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. The prementum bearing 26–36 major setae (usually 14+14 or 15+15). The body of the labial palps bearing 11–12 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 (but sometimes with a vestige on segment 4). The gizzard with 4–8 folds.
Distribution. Southern Scotland, northern England, English Midlands, East Anglia, Wales, southeast England, southwest England, Isle of Wight, Ireland, and central southern England (with Scottish records perhaps referable to S. nigrescens, with which the species is easily confused). Adults on the wing early June to early November (generally in best mature condition mid-July to late September).
Classification. Anisoptera; family Libellulidae.
General comments. A common and widespread species readily distinguishable from S. vulgatum by the narrow black band at the base of the frons not being continued down the inner sides of the eyes.
Illustrations. • Sympetrum striolatum (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’.