British insects: the families of Coleoptera
British insects: the families of Coleoptera | |
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 somewhat 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. Hind coxae posteriorly shaped to receive the retracted femur (with a transverse cavity). Tarsal segmentation formula 5, 5, 5. The tarsi without bilobed segments; without ‘hidden’ segments. Front tarsi with as many segments as the mid-tarsi; 5-segmented. Mid-leg tarsi 5-segmented; pentamerous. The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi simple to one-toothed or bifid; without an associated empodium. Hind tarsi with as many segments as the mid-tarsi, or with one segment fewer than the mid-tarsi; 5-segmented (rarely 4?). Elytral length/maximum width across the elytra 0.98–2.65. Elytra covering most to all 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. Exposed abdominal sternites 4, or 5; comprising both fused and movable components; immovably joined 2–5. Abdominal segment 8 with apparently functional spiracles, or apparently without functional spiracles.
Adult habitat, ecology. Not predacious; in dried plant material, under bark, and in stored plant products.
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). Larvae C-shaped with well developed legs, soft, head hypognathous with very small 3-segmented antennae, abdomen 10 segmented with the last one very small.
Classification. Suborder Polyphaga; Infraorder Bostrichiformia; Superfamily Bostrichoidea.
Worldwide and British representation. Genera about 20. 27 species in Britain; genera in Britain 17; Anobium, Ptinomorphus, Xyletinus, etc. E.g., Ptinomorphus imperialis; Xyletinus longitarsis (Serrated-horned Ptinus).
General comments. Small subcylindric or ovoid, reddish or dark brown beetles, with antennal insertions separated by more than the length of the scape; the hind coxae with a transverse concavity for reception of the femur..
Illustrations. • Anobium pertinax Linn. (Obstinate Death-watch beetle; cf. A. punctatum): B. Ent. 387. • Anobium pertinax (B. Ent. 387, legend+text. • Anobium pertinax (B. Ent. 387, text cont.. • Xyletinus longitarsis (Serrate-horned Ptinus: B. Ent. 375). • Xyletinus longitarsis (details, B. Ent. 375). • Xyletinus longitarsis: B. Ent. 375, legend+text. • Xyletinus longitarsis: B. Ent. 375, text cont.. • Anobium, Dryophilus, Grynobius, Hadrobregmus, Ptonomorphus (with Ptinidae): Fowler 4, 117 (1890). • Fowler 4, 117 (1890): original legend.. • Anitys, Coenocara, Dorcatoma, Ernobius, Lasioderma, Ochina, Ptilinus, Xestobium (with Stephanopachys): Fowler 4, 118 (1890). • Fowler 4, 118 (1890): original legend. • Ernobius abietis, with Cerambycidae etc.: Fowler Suppl. 16, 1913. • Fowler Suppl. 16, 1913: original legend. • 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: 2nd January 2012. http://delta-intkey.com’.
