British insects: the families of Coleoptera
British insects: the families of Coleoptera |
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= Limnebiidae.
Crawling Water-beetles.
General appearance. 1.1–1.7 mm long. Body length/maximum body width 1.6–2.57. Elytral length/pronotal length 1.77–3.62. 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 elongate; not necked; conspicuously waisted. Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. Eyes not strongly protuberant; without bristles. The maxillary palps conspicuously elongated, sometimes longer than the antennae. Antennae very short to about half the insect's head to tail length (perhaps with a respiratory function?); 7–11 segmented; clubbed. Antennal clubs 5 segmented; preceded by a cupule, or without a cupule. Antennal insertions hidden from above. Pronotal length/maximum pronotal width 0.42–1.05. Prothorax without notopleural sutures. Metaventrite without a transverse groove. Tarsal segmentation formula 4, 4, 4. The tarsi without bilobed segments; with a tiny basal segment that is hard to detect. Front tarsi with as many segments as the mid-tarsi; 5-segmented. Mid-leg tarsi 5-segmented; pentamerous, or pseudotetramerous. The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi simple; without an associated empodium. Hind tarsi with as many segments as the mid-tarsi; 5-segmented; not modified for swimming. Elytral length/maximum width across the elytra 1.18–2. Elytra exposing no more than part of the terminal tergite. Scutellary striole absent. Wings well developed, or absent or much reduced; fringed with long hairs on the hind margin, or not fringed. Exposed abdominal sternites 7; all articulated and movable. Abdominal segment 8 with apparently functional spiracles.
Adult habitat, ecology. Water-beetles (at least some breathing underwater via a film of air associated with the ventral abdominal hairs); moving in the water by alternate, walking leg movements; not predacious; phytophagous (on algae).
Larvae. Larvae non-aquatic (living in wet places, but easily drowned); not predacious; phytophagous (on algae?).
Classification. Suborder Polyphaga; Infraorder Staphyliniformia; Superfamily Staphilinoidea.
Worldwide and British representation. Genera at least 20. 29 species in Britain; genera in Britain 3; Hydraena, Limnebius, Ochthebius. E.g., Hydraena testacea (Testaceous Hydraena); Ochthebius punctatus (Irish Ochthebius); Ochthebius exsculptus (Gibson's Enicocerus).
Illustrations. • Hydraena testacea (Testaceous Hydraena: B. Ent. 307). • Hydraena testacea (details, B. Ent. 307). • Hydraena testacea: B. Ent. 307, legend+text. • Ochthebius punctatus (Irish Ochthebius: B. Ent. 250). • Ochthebius punctatus: B. Ent. 250, legend+text. • Ochthebius punctatus: B. Ent. 250, text cont.. • Ochthebius exsculptus (Gibson's Enicocerus): B. Ent. 291. • Ochthebius exsculptus: B. Ent. 291, legend+text. • Ochthebius exsculptus: B. Ent. 291, text cont.. • Hydraena britteni and Ochthebius subinteger, with Hydrophilidae and Staphylinidae: Fowler Suppl. 3, 1913. • Fowler Suppl. 3, 1913: original legend..
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: 2nd January 2012. http://delta-intkey.com’.
