Insects of Britain and Ireland: the families of Coleoptera

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L. Watson and M. J. Dallwitz


Including Corynetidae, Korynetidae, Thanerocleridae.


General appearance. 6–16 mm long. Body length/maximum body width 1.2–4.87. Elytral length/pronotal length 1.42–5.32. 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; somewhat conspicuously necked, or not necked; conspicuously waisted; often brightly coloured and patterned; exhibiting bright ‘warning colours’, or without ‘warning colouration’. Upper surfaces of body non-glabrous; exhibiting stiff, erect, dark bristles, or not bristly; with neither scales nor scale-like setae.

Detailed morphology. Beetles without a rostrum. Inclination of the head slight. Eyes strongly protuberant, or not strongly protuberant; bristly, or without bristles. The labrum at least partly visible in antero-dorsal view (nearly always), or concealed beneath the clypeus (Cylidrus); labrum mostly moderately to heavily sclerotized (mostly), or mostly membranous or only very lightly sclerotized (Cylidrus). Mandibles without a mola; with well developed prosthecae to without prosthecae. The mandibular apices simple, or bidentate or bilobed (some Korynetinae). The incisor edges of the mandibles with a single tooth, or with two or more teeth. The maxillae with distinct galea and lacinia apically to the palp. The apical segment of the maxillary palps cylindrical to fusiform, or somewhat expanded and truncate to subtriangular, or securiform to cultriform. The apical segment of the labial palps more or less expanded apically, or not expanded apically. Antennae short to long, but not exceeding the insect’s head to tail length; 9–11 segmented. Antennal scape not swollen. Antennae gradually expanding towards the apex, or clubbed (the club weakly defined). Antennal clubs 3–6 segmented. Antennal insertions visible from above, or hidden from above; usually not in fossae (?).

Cervical sclerites present. Prothorax longer than wide. Pronotal length/maximum pronotal width 0.5–1.52. The pronotum with lateral keels (pronotal carinae), or without lateral keels; keels when present, complete, or incomplete. Prothorax at its widest markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Scutellum conspicuous; elevated above the mesoscutum in lateral view, or not elevated; anteriorly simple; posteriorly broadly rounded or obtusely angulate, or truncate, or emarginate. The prosternal process present; variously complete, or incomplete; falling short of the mesoventrite to slightly overlapping the mesoventrite. Metaventrite without a transverse groove. The fore-leg coxae countersunk in ‘procoxal cavities’. The fore-leg coxal cavities open behind externally, or closed behind externally; broadly open, or narrowly open, or narrowly closed, or broadly closed; medianly confluent, or narrowly separated, or quite widely separated; slightly transverse, or circular to longer than wide; with narrow lateral extensions (some Tillinae), or without lateral extensions (mostly); internally open (mostly), or broadly closed internally (some Tillinae). The mid-leg coxae countersunk in ‘mesocoxal cavities’; separated by less than the shortest diameter of the cavity. The mid-leg coxal cavities contiguous (some Korynetinae), or narrowly separated, or moderately to widely separated; not or scarcely oblique (mostly), or markedly oblique (Cylidrus); open laterally, or closed laterally. Hind-leg coxae contiguous or narrowly separated (mostly), or widely separated (some Hydnocerinae); extending laterally to meet the elytra (mostly), or not markedly extended laterally (some Thaneroclerinae); not shaped posteriorly to receive the femur. Tarsal segmentation formula 5, 5, 5, or 4, 4, 4. The tarsi exhibiting bilobed segments; with a tiny basal segment that is hard to detect, or without ‘hidden’ segments. Front tarsi with as many segments as the mid-tarsi, or with one segment fewer than the mid-tarsi; 4-segmented, or 5-segmented. Mid-leg tarsi 4-segmented (the penultimate one), or 5-segmented; pentamerous, or pseudotetramerous, or tetramerous; 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 simple, or one-toothed or bifid, or serrate, denticulate or pectinate; with an empodium between them (this usually bisetose), or without an associated empodium. Hind tarsi with as many segments as the mid-tarsi, or with one segment fewer than the mid-tarsi; 4-segmented, or 5-segmented.

Elytral length/maximum width across the elytra 0.89–3.65. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite to at least three complete abdominal tergites; not truncate (distally rounded); non-glabrous. Elytra with six or more longitudinal lines of punctures, or apunctate, irregularly punctate, or each with fewer than 6 longitudinal lines of punctures or impressed striae; the lines per elytron when more than five, 9, or 10. Scutellary striole absent. Wings well developed, or absent or much reduced. Wings with an anal lobe, or without an anal lobe. Wings without a medial fleck. Abdominal sternites 5–6; all articulated and moveable. Abdominal segment 8 apparently without functional spiracles. The male external genitalia cucujiform.

Adult habitat, ecology. Predacious (on insects); on living vegetation and associated with flowers, or in rotting wood, or under bark.

Larvae. Mature larvae small to medium-sized to relatively large. The larvae elongate and more or less parallel-sided. Body circular in cross-section, or somewhat 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, or absent; on either side of the larval head when present, 1–5. The frontoclypeal suture between frons and clypeus indistinct or absent. The labrum and head capsule separated by a complete suture. Apices of the mandibles with a single lobe or tooth. The maxillary palps 3 segmented. The labium without ligula between the palps, or with a short ligula between the palps. Labial palps present and segmented; 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 (annular or annular biforous); without spiracular tubes. The abdominal apex without a respiratory chamber. Abdominal tergum 8 without amature. The last abdominal segment with cerci, or without cerci.

Larvae predacious; in rotting wood, in dried plant material, and under bark, or in carrion, or associated with fungi, or in dung, or in stored plant products (seemingly mainly feeding on insects (including other beetle larvae) in diverse habitats).

The larvae elongate, often unusually coloured, prognathous, antennae 3 segmented, the pronotum sclerotized, the 10-segmented abdomen with the last reduced or forming a foot.

Classification. Suborder Polyphaga; Infraorder Cucujiformia; Superfamily Cleroidea.

Representation in Britain and Ireland, and worldwide. About 3500 species worldwide. 14 species in Britain; genera in Britain 9; Korynetes, Necrobia, Opilo, Paratillus, Tarsostenus, Thanasimus, Thaneroclerus, Tillus, Trichodes. E.g., Necrobia violacea (Blue Corynetes); Necrobia ruficollis (Red-necked Necrobia); Tarsostenus univittatus (Shillingford's Opilus); Thanasimus formicarius (Ant-like Clerus); Tillus unifasciatus (Tillinae: Tricoloured Tillus); Trichodes alvearius (Bee-hive Beetle: extinct?.

General comments. The adult body clothed with erect bristles..

Illustrations. • Trichodes alvearius (Bee-hive Beetle: B. Ent. 044. Extinct in Britain). • Trichodes alvearius (details, B. Ent. 044). • Trichodes alvearius: B. Ent. 044, legend+text. • Trichodes alvearius: B. Ent. 044, legend+text. • Necrobia violacea (Blue Corynetes: B. Ent. 351). • Necrobia violacea: B. Ent. 351, legend+text. • Necrobia violacea: B. Ent. 351, text cont.. • Necrobia ruficollis (Red-necked Necrobia: B. Ent. 350). • Necrobia ruficollis: B. Ent. 350, legend+text. • Necrobia ruficollis: B. Ent. 350, text cont.. • Tarsostenus univittatus (extinct?):B. Ent. 270. • Tarsostenus univittatus : B. Ent. 270, legend+text. • Tarsostenus univittatus : B. Ent. 270, text cont.. • Thanasimus formicarius (Ant-like Clerus: B. Ent. 398). • Thanasimus formicarius: B. Ent. 398, legend+text. • Thanasimus formicarius: B. Ent. 398, text cont.. • Tillus unifasciatus (Tri-coloured Tillus, extinct?) B. Ent. 267. • Tillus unifasciatus: B. Ent. 267, legend+text. • Tillus unifasciatus: B. Ent. 267, text cont.. • Necrobia, Opilomollis, Tarsostenus, Thanasimus, Tillus (with Melyridae and Phloeophilus): Fowler 4, 115 (1890). • Fowler 4, 115 (1890): original legend.. • Necrobia rufipes, N. violacea and Korynetes caeruleus (with Lymexilidae, Ptiniidae and Drilus): Fowler 4, 116 (1890). • Fowler 4, 116 (1890): 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.’.