British Insects: the Odonata
Migrant Hawker Dragonfly.
Adults. Adults about 58–63–68 mm long. Average wingspan 85 mm; hindwings 37–40 mm long.
The eyes dorsally broadly contiguous; green (in females), or blue (in males).
Legs black. Thoracic antehumeral stripes absent. The wings spread more or less horizontally in repose; dissimilar in shape and venation; sessile; unpatterned and clear. The inner wing venation blackish. Discoidal cell divided longitudinally into a conspicuous triangle and supra-triangle. Antenodal veins in the forewings about 11–18 (fewer in the hindwings); incorporating two conspicuously stronger primaries, and those in the costal and subcostal spaces unaligned. Pterostigma well over twice but no more than five times as long as wide; dark brown (in the male), or light brown, or orange (orangish brown in the female).
Abdomen linear from a conspicuously swollen base; 45–48 mm long (female), or 44–49 mm long (male); predominantly dark brown (with yellow and blue or yellow and greenish markings); complexly patterned (spotted and interruptedly banded with yellow and blue in the male and yellow and greenish in the female); with a conspicuous, median yellow triangle on segment 2, or without a yellow triangle on segment 2; with mid-dorsal spots. Abdominal segments 9 and 10 unbanded, but each with a pair of rounded posterior 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, 30–38 mm long.
The eyes large; approaching one another closely at a point on the top of the head; convex dorsally, their posterior margins not aligned. The head in dorsal view not 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 shortly abruptly narrowed well before the hinge, with the prementum stalked to narrowed gradually to the hinge (the prementum relatively elongated). The prementum quite elongated, being nearly twice as long as the width of its front. The mask with a flat prementum. The prementum bearing 0 major setae. The body of the labial palps bearing 0 major setae. Distal margins of the labial palps entire. Legs shorter than the abdomen; fore- and middle tarsi 3-segmented.
The abdomen terminating in five short spine-like appendages; gizzard with 4–8 folds.
Distribution. Northern England, English Midlands, East Anglia, Wales, southeast England, southwest England, Isle of Wight, and central southern England (generally lacking from the north, and in Wales confined to south coastal localities). Adults on the wing late July to late October (generally in best mature condition mid-August to late September).
Classification. Anisoptera; family Aeshnidae.
Illustrations. • Aeshna mixta (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’.