. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. 278 CLASSIFICATION [CH. a little proximal to it. Quadrilateral variable in shape, but always free. Wings rarely coloured. Cross-veins usually more or less completely arranged in cross-sets. Abdomen slender. Body-pattern variable, often brightly coloured. Larva variable in form. Caudal gills usually lamellar, constricted, nodate, or subnodate, the division tending to disappear in the higher forms. Gizzard of 8-16 fields, variable in dentition. Subfamily 1. Megapodagrioninae (figs. 23 d, 143). Xodus placed at from one-third
. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. 278 CLASSIFICATION [CH. a little proximal to it. Quadrilateral variable in shape, but always free. Wings rarely coloured. Cross-veins usually more or less completely arranged in cross-sets. Abdomen slender. Body-pattern variable, often brightly coloured. Larva variable in form. Caudal gills usually lamellar, constricted, nodate, or subnodate, the division tending to disappear in the higher forms. Gizzard of 8-16 fields, variable in dentition. Subfamily 1. Megapodagrioninae (figs. 23 d, 143). Xodus placed at from one-third to one-fourth of the wing-length from the base (in Thamnatoneura, one-sixth). Quadrilateral somewhat irregular, the distal angle being acute but not sharply so; Cti^ leaves it without arching strongly upwards. Pterostigma regular, short or long. M^ leaves M^ nearer to nodus than to pterostigma, rarely half-way between. Nearly always Ms. Fig. Hindwing (45 mm.) of Podopteryx roseonotata Selys, 9, Queensland. Original. arises at subnodus, 31^ somewhat proximad to it. Axo in line with arculus (except Nesolesies). Main veins diverging towards distal end of wing, thus allowing development of intercalated sectors. Larva (Argiolestes) short, thick-set (fig. 42 a). Mask short, flat, without setae, resembling that of the EpaUaginae. Caudal gills in the form of simple lamellae, broadly fohate, horizontally spread out. Gizzard of 14-16 genera- lized fields. Subfamily 2. Pseudostigmatinae (fig. 144, also PI. I, fig. 8). Nodus placed very close to wing-base, at one-sixth to one-seventh of the entire length. J/, arising very far distad from nodus. Quadrilateral fairly regular, distal angle slightly acute. Postnodals very numerous, continued across the wing as complete transverse veins. Two or more intercalated sectors, with branches in the more richly veined forms. Pterostigma weak, diffuse, abnormal or absent. Abdomen very slender, excessively elongated. Fig. 144. Hindwing (62 mm.) of
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