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| Insects of Britain and Ireland: orders |
~ ThysanuraBristle-tails.
Adult insects. Phytophagous (including algae), or saprophagous, or mycophagous (and feeding on lichens); conspicuous ‘jumpers’ (by abrupt, downward flexing of the abdomen). Minute to small; flightless. Body more or less cylindrical (fusiform). Head hypognathous. Mouthparts well developed; of the biting type; not piercing; more or less conforming to the generalized biting type (regarded as “primitive”). Antennae conspicuous; simple; 15–35 segmented (i.e., “many-segmented”). Ocelli 3 (the lateral pair near the mid-line below the anterior margins of the large compound eyes, and transversely elongate). Tarsi 2 segmented (rarely), or 3 segmented. Abdomen conspicuously appendaged at the rear; with long terminal bristles; with cerci clearly visible at its tip (these long or fairly short, shorter than to sub-equalling the appendix dorsalis, with which they constitute three bristles terminating the abdomen; cf. Thysanura and Ephemeroptera). Abdomen of females with an exserted ovipositor. Abdomen apparently 11 segmented; exhibiting rudimentary abdominal limbs (in the form of reduced ‘abdominal styles’ on segments 2–9).
Larvae. Larvae with three pairs of segmented thoracic legs; without ventral abdominal prolegs. Development of larva into adult gradual; apterygote; not involving a pupal stage.
Classification. Subclass Apterygota.
British representation. Machilidae; genera 4; 7 species.
General comments. Very agile runners and jumpers, nocturnal, hiding by day under bark, in litter or in rock crevices.
Illustrations. • Petrobius (Lubbock 1862). Thysanura (Lepisma saccharina - Silverfish). Archaeognatha (Petrobius maritimus).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, 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. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. Insects of Britain and Ireland: orders. Version: 14th April 2022. delta-intkey.com’.
