British Insects: the Odonata
Highland Darter Dragonfly.
Adults. Adults about 31–34–37 mm long. Average wingspan 55 mm; hindwings 25–30 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 only briefly continued down the inner sides of the eyes.
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 to narrow-linear.
Abdomen linear from a conspicuously swollen base, or swollen both basally and distally and markedly constricted in between; 24–28 mm long; predominantly crimson red (in the male), or green, or yellow (olive-yellow, in the female); predominantly longitudinally lined (apart from median black dashes on segments 8 and 9 of both sexes, which are characteristic of the genus, and narrow yellow bands between the segments of the males, those of both sexes exhibit heavy black lateral markings); 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, 16.5–17.5 mm long.
The head in dorsal view markedly narrowing from immediately behind the eyes. The postocular lobes curving smoothly to the back of the head from immediately behind the eyes, or 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 31–32 major setae (15+16 to 16+16). The body of the labial palps bearing 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 4 to 8. The gizzard with 4–8 folds.
Distribution. Northern Scotland, southern Scotland, and Ireland. Adults on the wing early June to early October (generally in best mature condition early July to mid-September).
Classification. Anisoptera; family Libellulidae.
General comments. Distinguishable by the narrow black band at the base of the frons being continued, but only briefly, down the inner sides of the eyes; and more obviously by the heavy black markings on the sides of the thorax and abdomen.
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’.