Insects of Britain and Ireland: the families of Coleoptera
Soldier-beetles, Leatherwing beetles.
General appearance. 2–15 mm long. Body length/maximum body width 2.05–6.2. Elytral length/pronotal length 1.4–6.25. 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-oval to slender; dorsally flattened; not necked; somewhat waisted to conspicuously waisted. Upper surfaces of body non-glabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. The head not covered by the thorax. Inclination of the head slight to very strong. Eyes strongly protuberant, or not strongly protuberant; without bristles; finely facetted. The labrum concealed beneath the clypeus; labrum where recorded, mostly membranous or only very lightly sclerotized. Mandibles without a mola; with well developed prosthecae to without prosthecae. The mandibular apices simple. The incisor edges of the mandibles simple, or with a single tooth, or with two or more teeth (some Malthininae). The maxillae with distinct galea and lacinia apically to the palp. The apical segment of the maxillary palps securiform to cultriform, or aciculate (Malthininae only). The apical segment of the labial palps more or less expanded apically, or not expanded apically (Malthininae). Antennae short to longer than the insect's head to tail length; 11 segmented. Antennal scape not swollen. Antennae filiform. Antennal insertions visible from above; not in fossae.
Cervical sclerites present. Prothorax about as long as wide. Pronotal length/maximum pronotal width 0.46–1.25. The pronotum with lateral keels (pronotal carinae); keels complete. 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. Scutellum conspicuous; not elevated; anteriorly simple; posteriorly narrowly rounded or acute, or broadly rounded or obtusely angulate, or truncate, or emarginate. Metaventrite without a transverse groove. The fore-leg coxae attached externally, in the absence of procoxal cavities. The mid-leg coxae countersunk in mesocoxal cavities, or attached externally, in the absence of mesocoxal cavities; separated by when countersunk, less than the shortest diameter of the cavity. The mid-leg coxal cavities when present, contiguous; markedly oblique; when applicable, open laterally. Hind-leg coxae contiguous or narrowly separated; extending laterally to meet the elytra. Tarsal segmentation formula 5, 5, 5. The tarsi exhibiting 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 simple, or one-toothed or bifid; without an associated empodium. Hind tarsi with as many segments as the mid-tarsi; 5-segmented.
Elytral length/maximum width across the elytra 0.95–3.1. Elytra meeting along the length of the mid-line, or not meeting along the full length of the mid-line; covering most to all of the abdomen, or short, exposing several terminal abdominal tergites; exposing no more than part of the terminal tergite to at least three complete abdominal tergites; truncate (often), or not truncate; soft; smooth; non-glabrous. Elytra with six or more longitudinal lines of punctures (some Malthininae), 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 without an anal lobe. Wings without a medial fleck. Abdominal sternites 7–8; all articulated and moveable. Abdominal segment 8 with apparently functional spiracles. The male external genitalia cucujiform, or not classified.
Adult habitat, ecology. Predacious (mostly facultative predators feeding on soft-bodied insects, but also consuming plant material); generally on living vegetation and associated with flowers (mostly diurnally active).
Larvae. Mature larvae minute (less than 3 mm long) to relatively large. The larvae elongate and more or less parallel-sided. Body 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; on either side of the larval head 1. The frontoclypeal suture between frons and clypeus indistinct or absent. The labrum and head capsule completely fused, with no suture apparent. Apices of the mandibles with a single lobe or tooth. The maxillary palps 3 segmented, or 4 segmented. The labium without 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 entirely dorsal. The abdomen having functional spiracles on anterior segments (these annular); without spiracular tubes. The abdominal apex without a respiratory chamber. Abdominal tergum 8 without amature. The last abdominal segment without cerci.
Larvae predacious (usually, feeding on soft-bodied insects, including caterpillars and fly larvae), or not predacious (some species); commonly found in leaf litter, under bark or stones, in moss, or in the soil; if not predaceous, phytophagous.
Larvae equipped with channelled mandibles associated with paralyzing and extra-oral digestion of prey.
Classification. Suborder Polyphaga; Infraorder Elateriformia; Superfamily Cantharoidea.
Representation in Britain and Ireland, and worldwide. Genera about 50. 41 species in Britain; genera in Britain 6; Cantharis, Malthodes, Malthinus, Podabrus, Rhagonycha, Silis. E.g., Cantharis abdominalis var. cyanea; Cantharis decipiens; Rhagonycha testacea.
General comments. Adults elongate, flattened and parallel-sided, soft-bodied and usually finely pubescent; the labrum largely membranous. In common with Lycidae, Lymexylidae, Meloidae, some Dermestidae, some Melyridae and some Staphylinidae, the undersides of these beetles lack the usual procoxal cavities..
Illustrations. • Cantharis abdominalis var. cyanea Curtis (B. Ent. 215). • Cantharis abdominalis var. cyanea (details, B. Ent. 215). • Cantharis abdominalis var. cyanea: B. Ent. 215, legend+text. • Cantharis abdominalis var. cyanea: B. Ent. 215, text cont.. • Rhagonycha testacea (Testaceous Zonitis: B. Ent. 112. • Rhagonycha testacea (B. Ent. 112, legend+text). • Rhagonycha testacea (B. Ent. 112, text cont.). • Cantharis (10 spp., as Telephorus), Rhagonycha unicolor, R. fuscicornis and R. fulva: Fowler 4, 112 (1890). • Fowler 4, 112 (1890): original legend. • Rhagonycha (4 spp.), Malthinus (4 spp.), Malthodes (5 spp.): Fowler 4, 113 (1890). • Fowler 4, 113 (1890): original legend. • Cantharis (6 spp.), Podabrus and Silis, with Lampyridae: Fowler 4, 111 (1890). • Fowler 4, 111 (1890): original legend. • Cantharis figurata, with unrelated taxa: Fowler Suppl. 15, 1913. • Fowler Suppl. 15, 1913: original legend. • Cantharis decipiens (Rye & Fowler IX4).
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’.