British Insects: the Families of Coleoptera
British Insects: the Families of Coleoptera |
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Mud-beetles.
General appearance. 2.5–5 mm long. Body length/maximum body width 1.7–3.05. Elytral length/pronotal length 2.2–3.53. 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. Beetles elongate; not necked; conspicuously waisted. Upper surfaces of body non-glabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. Beetles prognathous. Inclination of the head slight. Eyes not strongly protuberant; without bristles; finely facetted. Antennae very short; strongly asymmetric; (9–)11 segmented. Antennal scape not swollen. Antennae clubbed. Antennal clubs 7 segmented (serrate); preceded by a cupule, or without a cupule. Antennal insertions visible from above; not in fossae.
Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.52–0.82. Prothorax at its widest not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Metaventrite with a transverse groove. The tarsi without bilobed segments; without ‘hidden’ segments (but the terminal segment about half as long as the basal three together). Mid-leg tarsi 4-segmented; tetramerous. Claws of the mid-leg tarsi not appendaged. Front tarsi with as many segments as the mid-tarsi; 4-segmented. Hind tarsi with as many segments as the mid-tarsi; 4-segmented. Tarsal claws simple. Elytral length/maximum width across the elytra 1.18–2.3. Elytra exposing no more than part of the terminal tergite; hard. Scutellary striole absent. Elytra non-glabrous (densely hairy). Wings well developed, or absent or much reduced.
Abdominal tergites 10. Visible abdominal sternites 5; immovably joined 3. Abdominal segment 8 with apparently functional spiracles.
Habitat, ecology. Land-dwellers; not predacious; phytophagous; in living vegetation, or in decaying plant material (found in stiff mud at the sides of ponds and streams).
Larvae. Larvae seemingly non-aquatic; not predacious; phytophagous; on living vegetation, or in decaying plant material (in mud).
Classification. Suborder Polyphaga; Superfamily Dryopoidea.
British representation. Genera 1; 8 species. E.g., Heterocerus obsoletus (Largest Heterocerus).
Illustrations. • Heterocerus obsoletus Curtis (Largest Heterocerus: B. Ent. 224). • Heterocerus obsoletus (details, B. Ent. 224). • Heterocerus obsoletus (B. Ent. 224, legend+text). • Heterocerus obsoletus (B. Ent. 224, text cont.).
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: 18th September 2008. http://delta-intkey.com’.
