British Insects: the Families of Coleoptera
British Insects: the Families of Coleoptera |
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General appearance. 1.5–1.8 mm long. Body length/maximum body width 1.3–2.15. Elytral length/pronotal length 2.4–4.7. Base of prothorax not or scarcely narrower than the combined elytral bases. Greatest prothoracic width not narrower or only slightly narrower than the greatest elytral width, or distinctly narrower than greatest elytral width. Beetles oval; dorsally strongly convex; not necked; not waisted. Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. Inclination of the head slight to very strong. Eyes strongly protuberant, or not strongly protuberant; without bristles. Antennae short; 7 segmented, or 10–11 segmented; weakly clubbed. Antennal clubs 1 segmented. Antennal insertions visible from above, or hidden from above. Mandibular prosthecae well developed.
Pronotal length/maximum pronotal width 0.3–0.65. Prothorax without notopleural sutures. Metaventrite with a transverse groove, or without a transverse groove. The tarsi without bilobed segments; without ‘hidden’ segments (in Britain). Mid-leg tarsi 5-segmented; pentamerous (in Britain). Claws of the mid-leg tarsi not appendaged. Front tarsi with as many segments as the mid-tarsi (in Britain); 5-segmented. Hind tarsi with as many segments as the mid-tarsi; 5-segmented. Tarsal claws simple. Elytra present. Elytral length/maximum width across the elytra 1–1.65. Elytra covering most of the abdomen; exposing no more than part of the terminal tergite. Scutellary striole absent. Wings well developed, or absent or much reduced.
Visible abdominal sternites 5; immovably joined 3, or 5–6. Abdominal segment 8 with apparently functional spiracles.
Habitat, ecology. Land-dwellers (but living on the margins of water courses).
General comments. The tarsi sometimes pseudopentamerous or tetramerous, and sometimes with lobed segments, in non-British species. The beetles’ ventral surface with cavities into which the legs can be folded.
Larvae. Larvae aquatic.
Classification. Suborder Polyphaga; Superfamily Dryopoidea.
British representation. Genera 1; 1 species.
Illustrations. • Limnichus pygmaeus (from Joy). Limnichus pygmaeus (Limnichidae). Eubria palustris (Psephenidae).
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 families of Coleoptera. Version: 9th June 2008. http://delta-intkey.com’.
