British insects: the families of Coleoptera
British insects: the families of Coleoptera | |
Fruitworm beetles.
General appearance. 3.5–5 mm long. Body length/maximum body width 1.45–2.72. Elytral length/pronotal length 3–3.5. 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, or distinctly narrower than greatest elytral width. Beetles elongate; cylindric; not necked; somewhat waisted to conspicuously waisted; deep yellow, covered with fine yellow pubescence. Upper surfaces of body non-glabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. Beetles without a rostrum. Eyes strongly protuberant, or not strongly protuberant; without bristles; finely facetted. Antennae very short to short; 11 segmented; clubbed. Antennal clubs 3 segmented. Pronotal length/maximum pronotal width 0.45–0.75. Prothorax with neither produced front corners nor serrated sides. Prothorax without notopleural sutures. Metaventrite without a transverse groove. Tarsal segmentation formula 5, 5, 4, or 4, 4, 4 (hard to interpret: the tarsi are velvety beneath, with five segments; the first and fourth segments are very small, with the latter hidden between the lobes of the third, and the fifth is as long as the rest together). The tarsi exhibiting bilobed segments (the second and third segments produced into long lappets); with a tiny penultimate segment hidden by distal lobing of the fourth and fused to the fifth and with a tiny basal segment that is hard to detect. Front tarsi with as many segments as the mid-tarsi; 5-segmented. Mid-leg tarsi 5-segmented; ambiguously pentamerous, or pseudotetramerous, or pseudotrimeous. The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi one-toothed or bifid (bent, with a strong tooth at the base beneath). Hind tarsi with as many segments as the mid-tarsi; 5-segmented. Elytral length/maximum width across the elytra 1.02–2.1. Elytra exposing no more than part of the terminal tergite. Scutellary striole present, or absent. Elytra non-glabrous (covered with silky yellow hairs). Wings well developed. Exposed abdominal sternites 5–6; all articulated and movable. Abdominal segment 8 apparently without functional spiracles.
Adult habitat, ecology. Land-dwellers; in living vegetation (associated with flowers).
Classification. Suborder Polyphaga; Superfamily Cucujoidea.
Worldwide and British representation. About 25 species worldwide (holarctic). 2 species in Britain; genera in Britain 1; Byturus. E.g., Byturus tomentosus.
General comments. Unwin represents the modified tarsi as “4,4,4 with some bilobed segments”, while Imms and Lawrence et al. settle for 5,5,5 ....
Illustrations. • Byturus tomentosus: B. Ent. 618. • Byturus tomentosus: B. Ent. 618, legend+text. • Byturus tomentosus: B. Ent. 618, text cont.. • Byturus tomentosus (with Cucujidae, Silvanidae etc.): Fowler 3, 93 (1889). • Fowler 3, 93 (1889): original legend.. • Byturus tomentosus (Janson 90).
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’.
