British Insects: the Families of Coleoptera
British Insects: the Families of Coleoptera |
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Including Ectrephidae, Gnostidae.
Death-watch Beetles, Woodworms.
General appearance. 1.3–7 mm long. Body length/maximum body width 1.35–3.63. Elytral length/pronotal length 1.4–4.7. 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 elongate-oval to elongate; dorsally more or less convex; not necked; not waisted to somewhat waisted. Upper surfaces of body glabrous or subglabrous, or non-glabrous; exhibiting stiff, erect, dark bristles, or not bristly; exhibiting scales or scale-like setae, or with neither scales nor scale-like setae.
Detailed morphology. The head covered by the thorax. Inclination of the head strong. Eyes strongly protuberant, or not strongly protuberant; bristly, or without bristles. Ocelli absent. Antennae very short to long, but not exceeding the insect’s head to tail length; (2–)9–11 segmented. Antennal scape not swollen. Antennae filiform, or clubbed, or serrate, or pectinate. Antennal clubs if present, 3 segmented. Antennal insertions visible from above, or hidden from above; ‘countersunk’ within saucer-like fossae. Mandibular prosthecae absent.
Pronotal length/maximum pronotal width 0.32–1.5. Prothorax without notopleural sutures. Metaventrite without 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, or with one segment fewer than the mid-tarsi; 4-segmented, or 5-segmented. Tarsal claws simple to one-toothed or bifid; without an associated empodium. Elytral length/maximum width across the elytra 0.98–2.65. Elytra covering most of the abdomen; exposing no more than part of the terminal tergite; hard. Scutellary striole present, or absent. Wings well developed, or absent or much reduced; fringed with long hairs on the hind margin, or not fringed.
Visible abdominal sternites 2, or 5; immovably joined 2, or 3, or 5–6. Abdominal segment 8 with apparently functional spiracles, or apparently without functional spiracles.
Habitat, ecology. Not predacious; in dried plant material, under bark, and in stored plant products.
General comments. The antennal insertions are separated by more than the length of the scape.
Larvae. Larvae not predacious; eating dried plant material or stored plant products and boring into dead wood; in rotting wood, in or under bark, and in stored plant products (notoriously boring in dead wood).
Classification. Suborder Polyphaga; Superfamily Bostrichoidea.
British representation. Genera 17 (Anobium, Ptinomorphus, etc.); 27 species. E.g., Ptinomorphus imperialis; Xyletinus longitarsis (Serrated-horned Ptinus).
Illustrations. • Anobium “pertinax” (Obstinate Death-watch beetle: B. Ent. 387. • Anobium “pertinax” (legend+text: B. Ent. 387. • Xyletinus longitarsis (Serrate-horned Ptinus: B. Ent. 375). • Xyletinus longitarsis (details, B. Ent. 375). • Xyletinus longitarsis (legend+text: B. Ent. 375). • Ptinomorphus imperialis (Rye & Fowler X1).
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’.
