British insects: the families of Coleoptera
British insects: the families of Coleoptera |
|
= Platystomidae; including Bruchelidae, Urodontidae.
Fungus weevils.
General appearance. 2.5–10 mm long. Body length/maximum body width 1.4–3. Elytral length/pronotal length 1.5–3. 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; not necked; somewhat waisted, or conspicuously waisted. Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly; exhibiting scales or scale-like setae, or with neither scales nor scale-like setae.
Detailed morphology. Beetles equipped with a rostrum (this short and flattened, by contrast with that of weevils). Inclination of the head slight to very strong. Eyes strongly protuberant, or not strongly protuberant; without bristles. The maxillary palps normal, flexible. Antennae short to long, but not exceeding the insect’s head to tail length; not elbowed; 9–11 segmented; without a much-elongated scape. Antennal scape not swollen. Antennae filiform, or clubbed. Antennal clubs when present, 3 segmented. Antennal insertions visible from above, or hidden from above; not in fossae. Mandibular prosthecae absent. Prothorax shorter than wide to longer than wide. Pronotal length/maximum pronotal width 0.4–1.15. Prothorax at its widest markedly narrower than the adjoining part of the abdomen, or not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Metaventrite without a transverse groove. Hind coxae not shaped posteriorly to receive the femur. Tarsal segmentation formula 4, 4, 4. The tarsi exhibiting bilobed segments; with a tiny penultimate segment hidden by distal lobing of the fourth and fused to the fifth. Front tarsi with as many segments as the mid-tarsi; 4-segmented, or 5-segmented (depending on interpretation). Mid-leg tarsi 4-segmented, or 5-segmented; pseudotetramerous. The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi simple, or one-toothed or bifid (sometimes toothed beneath); without an associated empodium. Hind tarsi with as many segments as the mid-tarsi; 4-segmented, or 5-segmented. Elytral length/maximum width across the elytra 0.85–2.1. Elytra exposing no more than part of the terminal tergite to at least one but fewer than three complete abdominal tergites. Scutellary striole present, or absent. Wings well developed, or absent or much reduced. Exposed abdominal sternites 5; comprising both fused and movable components; immovably joined 4 (only the apical one movable). Abdominal segment 8 apparently without functional spiracles.
Adult habitat, ecology. Not predacious (?); phytophagous; in living vegetation.
Larvae. Larvae not predacious; eating dried plant material or stored plant products (dead wood, galls), or mycetophagous; in rotting wood, in dried plant material, in fungi, and in stored plant products. Larvae curved, fleshy, widest in the middle, the head usually exserted and hypognathous, the antennae 1-segmented or absent; legs absent or very reduced.
Classification. Suborder Polyphaga; Superfamily Curculionoidea.
Worldwide and British representation. Genera about 400. 8 species in Britain; genera in Britain 6; Anthribus, Platystomos, etc. E.g., Anthribus retinosus, Platystomos albinus.
Illustrations. • Anthribus resinosus: B. Ent. 723. • Anthribus resinosus: B. Ent. 723, legend+text. • Anthribus resinosus: B. Ent. 723, text cont.. • Platystomos albinus: B. Ent. 726. • Platystomos albinus: B. Ent. 726, legend+text. • Platystomos albinus: B. Ent. 726, text cont.. • Anthribus resinosus, Brachytarsus (2 spp.), Choragus sheppardi, Platystomos albinus, Tropideres (2 spp., with Attelabidae and Nemonychidae): Fowler 5, 152 (1891). • Fowler 5, 152 (1891): original legend. • Anthribus resinosus, Platystomos albinus (Janson 232, 230). • Anthribus resinosus (Janson 232). • Brachytarsus “scabrosus” (= fasciatus? Rye & Fowler XI4).
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’.
