British Insects: the Insect Orders
British Insects: the Insect Orders | |
Book-lice, Psocids.
Adult insects. Phytophagous, or saprophagous, or consuming stored produce, or mycophagous. Minute to small. Body dorsiventrally flattened to laterally flattened (?). Head hypognathous. Mouthparts well developed; of the biting type; not piercing; conforming to the generalized biting type to highly modified (the mandibles asymmetric, the maxillary lacinia modified into an elongate, strongly sclerotized rod sunken well into the head capsule and apically variously toothed, the labial palpi reduced). Antennae conspicuous; simple; 15–35 segmented (‘many-segmented’). Ocelli 3 (in winged forms), or 0 (in apterous forms). Capable of flight, or flightless (not uncommonly). Wings when present, four; of similar texture in both pairs. Fore-wings membranous. Hind-wings smaller than the fore-wings; no broader than the fore-wings. Wings with few cross-veins (venation reduced); more or less naked. Wings of the resting insect closed and directed backwards; usually held roof-like over the abdomen. Tarsi 2 segmented, or 3 segmented. Abdomen not conspicuously appendaged; lacking clearly visible cerci; apparently 9 segmented; with no rudimentary abdominal limbs.
Larvae. Larvae with three pairs of segmented thoracic legs; without ventral abdominal prolegs. Development of larva into adult gradual; exopterygote; not involving a pupal stage.
Classification. Subclass Pterygota; Division Exopterygota.
British representation. 11 families; genera about 50; about 90 species.
Comments. Adults free living, feeding on plants, plant and animal remains, fungal hyphae, stored products, etc. Of little economic significance.
Illustrations. • 'Psocus fenestratus': B. Ent. 648. • 'Psocus fenestratus': B. Ent. 648, legend+text. • 'Psocus fenestratus Curtis': B. Ent. 648, text cont.. • Peripsocus phaeopterus, adult and nymph. Peripsocus phaeopterus. Adult. Young nymph.
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: the insect orders. Version: 9th June 2008. http://delta-intkey.com’.
