British Insects: the Families of Coleoptera
British Insects: the Families of Coleoptera |
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= Dytiscidae part; including Phreatodytidae.
Water-beetles.
General appearance. 4–4.5 mm long. Body length/maximum body width 1.38–2.1. Elytral length/pronotal length 2.05–3.75. Base of prothorax not or scarcely narrower than the combined elytral bases, or distinctly 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 not necked; yellowish- or reddish-brown. 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. Eyes two; not strongly protuberant; without bristles; finely facetted. Antennae short; 11 segmented; filiform. Antennal insertions hidden from above; not in fossae. Mandibular prosthecae present but reduced, or absent.
Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.4–0.65. Prothorax at its widest not markedly narrower than the adjoining part of the abdomen. Prothorax with notopleural sutures. Metaventrite without a transverse groove. Hind coxae immoveable. The tarsi without bilobed segments; without ‘hidden’ segments. Mid-leg tarsi 5-segmented; pentamerous. Claws of the mid-leg tarsi not appendaged. Front tarsi with as many segments as the mid-tarsi; 5-segmented. Hind tarsi with as many segments as the mid-tarsi; 5-segmented; modified for swimming, or not modified for swimming. Tarsal claws simple. Elytral length/maximum width across the elytra 0.92–1.56. Elytra exposing no more than part of the terminal tergite; glossy. Scutellary striole absent. Wings well developed, or absent or much reduced.
Visible abdominal sternites 4–6; immovably joined 0, or 2, or 3. Abdominal segment 8 with apparently functional spiracles.
Habitat, ecology. Water-beetles; diving and ‘rowing’ by parallel-simultaneous leg movements; predacious, or not predacious (?).
General comments. Dorsally very convex, boat-shaped, the scutellum invisible.
Larvae. Larvae aquatic; probably predacious (but not digesting extra-orally).
Classification. Suborder Adephaga; Superfamily Caraboidea.
British representation. Genera 1; 2 species. E.g., Noterus clavicornis (Marsham's Noterus Water-beetle).
Illustrations. • Noterus clavicornis (Marsham's Water-beetle: B. Ent. 236). • Noterus clavicornis (details, B. Ent. 236). • Noterus clavicornis: B. Ent. 236, legend+text.
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’.
