Insects of Britain and Ireland: the families of Coleoptera

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L. Watson and M. J. Dallwitz


Including Schizopodidae.

Jewel Beetles.

General appearance. 2.3–12 mm long. Body length/maximum body width 1.25–5.15. Elytral length/pronotal length 2–6.83. 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. Body not noticeably widest either behind the thorax, or at the rear. Beetles elongate-oval, or elongate; not necked; conspicuously waisted; brightly metallic; 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. Inclination of the head slight to very strong. Eyes strongly protuberant, or not strongly protuberant; without bristles; finely facetted. The labrum at least partly visible in antero-dorsal view; labrum mostly moderately to heavily sclerotized. Mandibles without a mola; without prosthecae. The mandibular apices simple, or bidentate or bilobed. The incisor edges of the mandibles simple, or with a single tooth. The maxillae with distinct galea and lacinia apically to the palp, or with a single apical structure additional to the palp (some Agrilinae). The apical segment of the maxillary palps cylindrical to fusiform. The apical segment of the labial palps not expanded apically. Antennae very short to about half the insect's head to tail length; (10–)11(–12) segmented. Antennal scape not swollen. Antennae filiform (sometimes, more or less), or clubbed (occasionally, weakly), or serrate (usually). Antennal insertions visible from above, or hidden from above; ‘countersunk’ within saucer-like fossae (some Agrilinae), or not in fossae.

Cervical sclerites present. Prothorax shorter than wide to about as long as wide. Pronotal length/maximum pronotal width 0.2–0.95. The pronotum with lateral keels (pronotal carinae), or without lateral keels (some Buprestinae); keels when present, complete, or incomplete. Posterior edge of the pronotum distinctly crenulate, or not crenulate. Prothorax at its widest not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Scutellum conspicuous to highly reduced, or absent; when present, usually elevated above the mesoscutum in lateral view. The prosternal process complete; moderately or strongly overlapping the mesoventrite to concealing most or all of the mesoventrite. Metaventrite with a transverse groove. The fore-leg coxae countersunk in ‘procoxal cavities’. The fore-leg coxal cavities open behind externally; broadly open; quite widely separated; slightly transverse, or circular to longer than wide; with narrow lateral extensions, or without lateral extensions; internally open. The mid-leg coxae countersunk in ‘mesocoxal cavities’; separated by less than the shortest diameter of the cavity (some Buprestinae), or more than the shortest diameter of the cavity. The mid-leg coxal cavities moderately to widely separated; not or scarcely oblique; open laterally. Hind-leg coxae contiguous or narrowly separated; extending laterally to meet the elytra; posteriorly shaped to receive the retracted femur (with a backwardly facing concavity). 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 1–3.2. Elytra exposing no more than part of the terminal tergite, or at least three complete abdominal tergites; hard; striate. Elytra with six or more longitudinal lines of punctures, or with six or more impressed striae, 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 to 11. Scutellary striole present, or absent. Wings well developed. Wings without an anal lobe. Wings without a medial fleck. Abdominal sternites 4–7; all articulated and moveable, or comprising both fused and moveable components. Basal abdominal sternites immovably joined when present 2. Abdominal segment 8 with apparently functional spiracles. The male external genitalia buprestoid.

Adult habitat, ecology. On living vegetation and associated with flowers (especially on tree trunks and nectarial flowers); phytophagous.

Larvae. Mature larvae variable in size, minute (less than 3 mm long), or small to medium-sized. The larvae elongate and more or less parallel-sided. Body circular in cross-section to somewhat flattened, or strongly flattened (Agrilinae). Vestiture restricted to fine hairs or setae. The larvae dorsally only very lightly pigmented or sclerotized; ventrally only very lightly pigmented. The antennae 2 segmented. Stemmata present, or absent (usually); on either side of the larval head when present, 2 (Agrilinae). The frontoclypeal suture between frons and clypeus distinct. The labrum and head capsule separated by a complete suture. Apices of the mandibles bilobed or bidentate, or trilobed or tridentate. The maxillary palps 2 segmented. The labium with a ligula at least as long as the palps. Labial palps present and segmented, or absent or non-segmented (Agrilinae); when present, i.e. usually, 1 segmented. Mesothoracic legs much reduced or absent; 0 segmented (in Agrilinae), or 1–2 segmented; when developed with 1 moveable claw. Visible abdominal segments 10. Tergum 9 of the abdomen entirely dorsal. The abdomen having functional spiracles on anterior segments (these cribriform); without spiracular tubes. The abdominal apex without a respiratory chamber. Abdominal tergum 8 without amature. The last abdominal segment without cerci.

Larvae in living vegetation, or in decaying plant material, or in rotting wood (often feeding in the cambium and younger wood of trees (including roots), or in stems of herbaceous plants, also some leaf miners); phytophagous.

Larvae soft-bodied and legless, the head small and retracted without ocelli, the labrum free, the antennae very short, the prothorax markedly expanded and flattened, and the hind body relatively slender.

Classification. Suborder Polyphaga; Infraorder Elateriformia; Superfamily Buprestoidea.

Representation in Britain and Ireland, and worldwide. About 15000 species worldwide; genera about 450. 12 species in Britain; genera in Britain 5; Agrilus, Anthaxia, Aphanisticus, Melanophila, Trachys. E.g., Agrilus sinuatus (Gold-and-purple Agrilus); Aphanisticus pusillus (Smallest Buprestid); Anthaxia nitidula (Glittering Buprestid).

General comments. Adult metaventrite (= metasternum) with a transverse groove, by contrast with Chrysomelidae, and the eyes very large and higher than wide, by contrast with Drilidae..

Illustrations. • Agrilus sinuatus (Gold-and-purple Agrilus: B. Ent. 067). • Agrilus sinuatus (B. Ent. 67. legend+text). • Agrilus sinuatus (B. Ent. 67. text cont.). • Aphanisticus pusillus (Smallest Buprestid: B. Ent. 262). • Aphanisticus pusillus: B. Ent. 262, legend+text. • Aphanisticus pusillus: B. Ent. 262, text cont.. • Anthaxia nitidula (Glittering Buprestis: B. Ent. 031). • Anthaxia nitidula (details, B. Ent. 031). • Anthaxia nitidula: B. Ent. 031, legend+text. • Anthaxia nitidula: B. Ent. 031, text cont.. • Trachys minuta: B. Ent. 686. • Trachys minuta: B. Ent. 686, legend+text. • Trachys minuta: B. Ent. 686, text cont.. • Agrilus (3 spp.), Anthaxia, Aphanisticus, Trachys (3 spp., with Eucnemidae, Throscidae, etc.): Fowler 4, 104 (1890). • Fowler 4, 104 (1890): original legend. • Aphanisticus emerginatus and Melanophila acuminata, with unrelated taxa: Fowler Suppl. 15, 1913. • Fowler Suppl. 15, 1913: original legend. • Trachys minuta (Janson186).

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.’.