Insects of Britain and Ireland: the families of Coleoptera
General appearance. 3–12 mm long (?). Body length/maximum body width 1.95–2.2. Elytral length/pronotal length 1.9–5.5. Base of prothorax distinctly narrower than the combined elytral bases. Greatest prothoracic width distinctly narrower than greatest elytral width. Body not noticeably widest either behind the thorax, or at the rear. Beetles oval to elongate-oval; dorsally somewhat convex to dorsally strongly convex; not necked; somewhat waisted to conspicuously waisted; decidedly short-legged. Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. Beetles equipped with a rostrum; prognathous. Inclination of the head slight. Eyes strongly protuberant; without bristles; finely facetted. Ocelli absent. The labrum at least partly visible in antero-dorsal view; labrum mostly moderately to heavily sclerotized. Mandibles with a reduced mola; with well developed prosthecae. The mandibular apices simple, or bidentate or bilobed. The incisor edges of the mandibles with a single tooth, or with a single tooth. The maxillae with distinct galea and lacinia apically to the palp. The apical segment of the maxillary palps somewhat expanded and truncate to subtriangular. The apical segment of the labial palps more or less expanded apically, or not expanded apically. Antennae short; 11 segmented. Antennal scape not swollen. Antennae filiform. Antennal insertions visible from above; not hidden by lateral extensions of the frons.
Cervical sclerites present. Prothorax shorter than wide to about as long as wide (widest posteriorly). Pronotal length/maximum pronotal width 0.6–0.85. The pronotum with lateral keels (pronotal carinae); keels incomplete. Prothorax without notopleural sutures. Scutellum conspicuous; elevated above the mesoscutum in lateral view; anteriorly simple; posteriorly narrowly rounded or acute. The prosternal process complete, or incomplete; falling short of the mesoventrite. Metaventrite without a transverse groove. The fore-leg coxae countersunk in procoxal cavities. The fore-leg coxal cavities open behind externally; narrowly open; narrowly separated; circular to longer than wide; without lateral extensions; internally closed by a slender bar. The mid-leg coxae countersunk in mesocoxal cavities; separated by less than the shortest diameter of the cavity. The mid-leg coxal cavities narrowly separated, or moderately to widely separated; not or scarcely oblique; closed laterally. Hind-leg coxae contiguous or narrowly separated; not markedly extended laterally; not shaped posteriorly to receive the femur. Tarsal segmentation formula 5, 5, 4. 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 penultimate segment not distinctly shorter than the antepenultimate one. The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi one-toothed or bifid; without an associated empodium. Hind tarsi with one segment fewer than the mid-tarsi; 4-segmented.
Elytral length/maximum width across the elytra 1.48–1.63. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite; not truncate; without striae (apunctate or irregularly punctate). Elytra apunctate, irregularly punctate, or each with fewer than 6 longitudinal lines of punctures or impressed striae. Scutellary striole absent. Elytra with epipleura. Elytral epipleura reaching to the tips of the elytra. Wings well developed. Wings without an anal lobe. Wings with a medial fleck, or without a medial fleck; the medial fleck if present, not bisected by a vein. Abdominal sternites 5; comprising both fused and moveable components. Basal abdominal sternites immovably joined 3 (4 connte with 3 and 5). Abdominal segment 8 apparently without functional spiracles. The male external genitalia tenebrionoid.
Adult habitat, ecology. Not predacious (?); associated with flowers.
Larvae. Mature larvae small to medium-sized to relatively large (?). The larvae elongate and more or less parallel-sided. Body strongly flattened. Vestiture restricted to fine hairs or setae. The larvae dorsally only very lightly pigmented or sclerotized; ventrally only very lightly pigmented. The antennae 3 segmented. Stemmata present; on either side of the larval head 2, or 5. The frontoclypeal suture between frons and clypeus indistinct or absent. The labrum and head capsule separated by a complete suture. Apices of the mandibles bilobed or bidentate, or trilobed or tridentate. The maxillary palps 3 segmented. The labium with a short ligula between the palps, or with a ligula at least as long as the palps. Labial palps present and segmented; 1 segmented, or 2 segmented. Mesothoracic legs present and segmented; 5 segmented; with 1 moveable claw. Visible abdominal segments 10. Tergum 9 of the abdomen extending to the underside. The abdomen having functional spiracles on anterior segments (these annular or annular-multiforous); without spiracular tubes. The abdominal apex without a respiratory chamber. Abdominal tergum 8 without amature. The last abdominal segment with cerci.
Larvae usuallu found under bark; consuming decaying plant material and consuming rotting wood (?).
Classification. Suborder Polyphaga; Infraorder Cucujiformia; Superfamily Tenebrionoidea.
Representation in Britain and Ireland, and worldwide. About 50 species worldwide. 1 species in Britain (M. curculionoides); genera in Britain 1; Mycterus.
Illustrations. • Mycterus curculionoides, with Scraptiidae, Oedemeridae, Pyrochroidae, Mordellidae: Fowler 5, 149 (1891). • Fowler 5, 148 (1891): original legend..
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. Insects of Britain and Ireland: the families of Coleoptera. Version: 16th May 2016. delta-intkey.com’.