Insects of Britain and Ireland: the families of Coleoptera

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L. Watson and M. J. Dallwitz


Including Ischaliidae, Lagriidae part, Melöidae part, Notoxidae, Pedilidae part, Pyrochroidae part.

General appearance. 2.5–4.5 mm long. Body length/maximum body width 1.9–3.8. Elytral length/pronotal length 1.9–5.1. 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; conspicuously necked, or not necked (the neck then hidden by a forwardly-directed projection from the thorax); somewhat waisted to conspicuously waisted; brown, black or red, often banded or spotted; exhibiting bright ‘warning colours’, or without ‘warning colouration’. Upper surfaces of body glabrous or subglabrous, or non-glabrous; exhibiting stiff, erect, dark bristles, or not bristly; exhibiting scales or scale-like setae, or with neither scales nor scale-like setae.

Detailed morphology. Beetles prognathous, or not prognathous. Inclination of the head slight, or strong. Eyes strongly protuberant, or not strongly protuberant; bristly, or without bristles. Ocelli absent. The labrum at least partly visible in antero-dorsal view; labrum mostly moderately to heavily sclerotized. Mandibles with a well developed mola; with well developed prosthecae to without prosthecae. The mandibular apices simple, or bidentate or bilobed, or multidentate or multilobed. The incisor edges of the mandibles simple. 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 not expanded apically. Antennae short to about half the insect's head to tail length; 11–12 segmented. Antennal scape swollen to not swollen. Antennae filiform (or moniliform), or gradually expanding towards the apex. Antennal insertions visible from above, or hidden from above; not in fossae.

Cervical sclerites present. Prothorax longer than wide. Pronotal length/maximum pronotal width 0.73–1.9. The pronotum without lateral keels. Prothorax at its widest markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Scutellum conspicuous to highly reduced; not elevated; anteriorly simple; posteriorly narrowly rounded or acute, or broadly rounded or obtusely angulate. The prosternal process present, or absent; when present, incomplete; when present, 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; broadly open; medianly confluent; circular to longer than wide; without lateral extensions; broadly closed internally. The mid-leg coxae countersunk in ‘mesocoxal cavities’; separated by less than the shortest diameter of the cavity. The mid-leg coxal cavities contiguous, or narrowly separated, or moderately to widely separated; not or scarcely oblique to markedly oblique; open laterally, or closed laterally. Hind-leg coxae contiguous or narrowly separated, or widely separated; extending laterally to meet the elytra, or not markedly extended laterally; not shaped posteriorly to receive the femur. Tarsal segmentation formula 5, 5, 4. 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, or serrate, denticulate or pectinate; with an empodium between them (this with no more than two setae), or without an associated empodium. Hind tarsi with one segment fewer than the mid-tarsi; 4-segmented.

Elytral length/maximum width across the elytra 1.35–3.7. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite to at least three complete abdominal tergites; non-glabrous; striate, or without striae. 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 present, 10. Scutellary striole present, or absent. Elytra without epipleura. Wings well developed, or absent or much reduced. Wings with an anal lobe. Wings with a medial fleck, or without a medial fleck; the medial fleck when present, bisected by a vein, or not bisected by a vein. Abdominal sternites 4–5; all fused and immoveable. Abdominal segment 8 apparently without functional spiracles. The male external genitalia trilobate, or tenebrionoid, or not classified.

Adult habitat, ecology. Not predacious; on living vegetation, in decaying plant material, in rotting wood, associated with dung, and associated with flowers (seemingly saprophagous in various habitats, but often found on flowers).

Larvae. Mature larvae minute (less than 3 mm long), or small to medium-sized. 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 separated by a complete suture. Apices of the mandibles bilobed or bidentate. The maxillary palps 3 segmented. The labium 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 (these annular); without spiracular tubes. The abdominal apex without a respiratory chamber. Abdominal tergum 8 without amature. The posterior segments without swimming hairs. The last abdominal segment with cerci.

Larvae not predacious (?); in decaying plant material; consuming decaying plant material (?).

Classification. Suborder Polyphaga; Infraorder Cucujiformia; Superfamily Tenebrionoidea.

Representation in Britain and Ireland, and worldwide. About 3000 species worldwide; genera about 100. 16 species in Britain; genera in Britain 2; Anthicus, Notoxus. E.g., N. monoceros, A. instabilis.

General comments. Slender beetles of small to moderate size, the pubescent body brown, black or red and often banded or spotted. Probably mostly omnivorous detritovores.

Illustrations. • Anthicus instabilis: B. Ent. 714. • Anthicus instabilis: B. Ent. 714, legend+text. • Anthicus instabilis: B. Ent. 714, text cont.. • Anthicus (7 spp.) and Notoxus paradoxus (cf. N. monoceros?, with Anaspis and Metoecus): Fowler 5, 150 (1891). • Fowler 5, 150 (1891): original legend.. • Anthicus bimaculatus, with Aderidae and Melo´dae: Fowler 5, 151 (1891). • Fowler 5, 151 (1891): original legend.. • Anthicus instabilis (Janson 164, 144). • Nototoxus monoceros (Rye & Fowler X5).

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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.’.