British Insects: the Odonata
Brown Hawker Dragonfly.
Adults. Adults about 68–73–78 mm long. Average wingspan 102 mm; hindwings 41–49 mm long.
The eyes dorsally broadly contiguous; brown and green, or brown and blue.
Legs dark brown. Thoracic antehumeral stripes absent. The wings spread more or less horizontally in repose; dissimilar in shape and venation; sessile; colour tinted throughout. The tinting amber. The inner wing venation brown. Discoidal cell divided longitudinally into a conspicuous triangle and supra-triangle. Antenodal veins in the forewings about 18–22 (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; reddish brown.
Abdomen linear from a conspicuously swollen base (briefly somewhat constricted behind the swelling in the male); 49–54 mm long (female), or 54–60 mm long (male); predominantly dark brown; complexly patterned (both sexes with narrow yellow interrupted bands, and blue spots on segments 2 and 3 in the male); without a yellow triangle on segment 2; with mid-dorsal spots (these lateral and whitish in the male), or without mid-dorsal spots (in the female). Abdominal segments 9 and 10 neither colour-banded nor colour-spotted. 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, 40–46 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 narrowed gradually to the hinge (its length much less than twice the front width). The prementum relatively short, being much less than twice as long as its front width. The mask with a flat prementum; with a short slit-like median cleft. 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, southeast England, Ireland, and central southern England. Adults on the wing early June to late October (generally in best mature condition mid-June to mid-September).
Classification. Anisoptera; family Aeshnidae.
Illustrations. • Aeshna grandis (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’.