British insects: the families of Coleoptera
British insects: the families of Coleoptera | |
~Bostrychidae-Lyctinae.
Powder-post Beetles.
General appearance. 2.7–6 mm long. Body length/maximum body width 2.45–3.65. Elytral length/pronotal length 2.6–3.25. 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; dorsally flattened; not necked; conspicuously waisted. Upper surfaces of body non-glabrous; not bristly; exhibiting scales or scale-like setae, or with neither scales nor scale-like setae.
Detailed morphology. Eyes strongly protuberant; without bristles; finely facetted. Antennae short; 11 segmented. Antennal scape not swollen. Antennae clubbed. Antennal clubs 2 segmented. Antennal insertions hidden from above (but head visible from above). Mandibular prosthecae present but reduced, or absent. Pronotal length/maximum pronotal width 0.8–1.16. Prothorax without notopleural sutures. Metaventrite without a transverse groove. Tarsal segmentation formula 5, 5, 5. The tarsi without bilobed segments; with a tiny penultimate segment hidden by distal lobing of the fourth and fused to the fifth (pseudotrimerous), or without ‘hidden’ segments. Front tarsi with as many segments as the mid-tarsi; 4-segmented, or 5-segmented. Mid-leg tarsi 4-segmented, or 5-segmented; pentamerous, or pseudotrimeous. The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi simple. Hind tarsi with as many segments as the mid-tarsi; 4-segmented, or 5-segmented. Elytral length/maximum width across the elytra 1.65–2.7. Elytra exposing no more than part of the terminal tergite. Scutellary striole present. Elytra non-glabrous. Wings well developed. Exposed abdominal sternites 5 (the first almost as long as the second and third together); all articulated and movable, or comprising both fused and movable components; immovably joined when present, 2. Abdominal segment 8 with apparently functional spiracles.
Adult habitat, ecology. Not predacious; eating dried plant material or stored plant products (e.g., dried plant roots), or boring into dead wood; in rotting wood and in dried plant material (in dry herb roots, and in dead wood: associated with felled oaks).
Larvae. Larvae not predacious; eating dried plant material or stored plant products and boring into dead wood; in rotting wood and in dried plant material (in dry herb roots, and in dead wood: associated with felled oaks, seemingly avoiding coniferous wood). The larvae C-shaped, white, head partly buried in the prothorax, with 3-segmented antennae, the mouthparts directed forwards; the abdomen 10 segmented with the last one small.
Classification. Suborder Polyphaga; Infraorder Bostrichiformia; Superfamily Bostrichoidea.
Worldwide and British representation. About 70 species worldwide; genera 4. 6 species in Britain; genera in Britain 2; Lyctus, Trogoxylon. E.g., L. brunneus, L. fuscus.
General comments. Small, parallel-sided, flattened beetles, the thorax sculptured, with longitudinal costae; notorious woodborers, destructively attacking wood products..
Illustrations. • Lyctus linearis (as canaliculatus) and L. brunneus, with Cisidae etc.: Fowler 4, 119 (1890). • Fowler 4, 119 (1890): original legend.. • Lyctus brunneus, Lyctus linearis.
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’.
