British Insects: the Families of Coleoptera
British Insects: the Families of Coleoptera |
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= Elmididae, Elminthidae, Helmidae, Helminthidae, Limniidae.
Water-beetles.
General appearance. 1.8–4 mm long. Body length/maximum body width 1.8–3.1. Elytral length/pronotal length 1.8–4.7. 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 oval to elongate-oval; not necked; somewhat waisted; conspicuously long-legged. 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 strong. Eyes not strongly protuberant; without bristles. Antennae short; 7–11 segmented. Antennal scape not swollen. Antennae filiform. Antennal insertions visible from above; not in fossae.
Pronotal length/maximum pronotal width 0.6–1.1. Prothorax without notopleural sutures. Metaventrite with a transverse groove. 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. Tarsal claws simple, or one-toothed or bifid. Elytral length/maximum width across the elytra 1.3–2.5. Elytra exposing no more than part of the terminal tergite. Scutellary striole present, or absent. Wings well developed, or absent or much reduced.
Visible abdominal sternites 5–6; immovably joined 3. Abdominal segment 8 with apparently functional spiracles, or apparently without functional spiracles.
Habitat, ecology. Water-beetles (in running water); moving in the water by alternate, walking leg movements; not predacious; phytophagous; in living vegetation.
Larvae. Larvae aquatic; not predacious; phytophagous; on living vegetation.
Classification. Suborder Polyphaga; Superfamily Dryopoidea.
British representation. Genera 8; 11 species. E.g., Limnius volkmari (Volckmar's Elmis Water-beetle).
Illustrations. • Limnius volckmari (Volckmar's Water-beetle: bent294). • Limnius volckmari (details, B. Ent. 294). • Limnius volckmari: B. Ent. 294, 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’.
