British Insects: the Odonata
Broad-bodied Chaser Dragonfly.
Adults. Adults about 40–44–48 mm long (the somewhat shorter female 42–44 mm). Average wingspan 76 mm; hindwings 33–37 mm long.
The eyes dorsally narrowly apposed to dorsally broadly contiguous; brown.
Legs black and brown (mostly black, but brown at the femoral bases). Thoracic antehumeral stripes present (these broad); green, or green to yellow. The wings spread more or less horizontally in repose; dissimilar in shape and venation; sessile; with a sharply defined, dark brown basal fascia. The inner wing venation blackish. Discoidal cell divided longitudinally into a conspicuous triangle and supra-triangle. Antenodal veins in the forewings 14–18 (fewer in the hindwings). Pterostigma well over twice but no more than five times as long as wide; black.
Abdomen broadly lanceolate; 24–28 mm long; predominantly usually with yellowish lateral markings, pruinescent sky blue (in mature males), or brown (in females and immature males); plain (in the mature male), or predominantly longitudinally lined (the female with a large, conspicuous, yellow spot or longitudinal band on either side of the middle abdominal segments); with mid-dorsal spots, or 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, 22.5–25 mm long.
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; having the prementum hollowed dorsally; without a median cleft. The prementum bearing 18–22 major setae (9+9 to 11+11, with two medial fields of three to five short setae slightly anterior to these). The body of the labial palps bearing 8–12 major setae. Distal margins of the labial palps weakly crenate, or finely toothed. 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 (and sometimes with a vestige on 3). The abdomen with a prominent mid-dorsal spine on segment 8; gizzard with 4–8 folds.
Distribution. Northern England, English Midlands, East Anglia, Wales, southeast England, southwest England, Isle of Wight, and central southern England. Adults on the wing late April to early September (generally in best mature condition mid-May to late July).
Classification. Anisoptera; family Libellulidae.
Illustrations. • Libellula depressa (from Lucas). • Libellula depressa (from Shaw and Nodder, 1800). • Libellula depressa: nymph (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’.