Insects of Britain and Ireland: the families of Coleoptera

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L. Watson and M. J. Dallwitz


= Anisotomidae, Liodidae; including Camiaridae, Catopidae, Cholevidae, Colonidae, Leptodiridae, Sogdidae; excluding Platypsillinae (Leptinidae).

Truffle Beetles.

General appearance. 1.2–7 mm long. Body length/maximum body width 1.2–4.05. Elytral length/pronotal length 1.05–4.2. 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 oval to elongate-oval; not necked; not waisted to somewhat waisted. Upper surfaces of body glabrous or subglabrous, or non-glabrous; exhibiting stiff, erect, dark bristles, or not bristly; with neither scales nor scale-like setae. Beetles rolling into a ball when alarmed (sometimes), or not conglobulating.

Detailed morphology. Inclination of the head slight to strong. Eyes strongly protuberant, or not strongly protuberant; bristly, or without bristles. Ocelli present, or absent; when present, paired. The labrum at least partly visible in antero-dorsal view; labrum mostly moderately to heavily sclerotized. Mandibles with a well developed mola, or with a reduced mola, or without a mola (some Leiodinae); 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 Sogdini). The maxillae with distinct galea and lacinia apically to the palp. The apical segment of the maxillary palps cylindrical to fusiform. The apical segment of the labial palps not expanded apically. Antennae short to long, but not exceeding the insect’s head to tail length; 3 segmented, or 9–11 segmented; clubbed (the club sometimes elongate). Antennal clubs 5 segmented. Antennal segment 8 within the club, smaller than segments 7 and 9. Antennal insertions visible from above, or hidden from above; not in fossae.

Cervical sclerites present, or absent (Coloninae). Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.35–4.35. The pronotum with lateral keels (pronotal carinae); keels complete. Prothorax at its widest not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Hind corners of the thorax not extended rearwards into sharp points. Scutellum conspicuous; not elevated; anteriorly simple; posteriorly narrowly rounded or acute, or broadly rounded or obtusely angulate. The prosternal process present, or absent; when present, complete, or 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, or narrowly open; medianly confluent, or narrowly separated; strongly transverse to slightly transverse; with narrow lateral extensions, or without lateral extensions; internally open, or broadly closed internally. The mid-leg coxae countersunk in ‘mesocoxal cavities’; separated by less than the shortest diameter of the cavity, or more 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, or markedly oblique (Sogdini only); open laterally. Hind-leg coxae contiguous or narrowly separated; not markedly extended laterally. Tarsal segmentation formula 5, 5, 5, or 5, 5, 4, or 5, 3, 3, or 4, 3, 3. The tarsi without 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; 3-segmented, or 4-segmented, or 5-segmented. Mid-leg tarsi 3-segmented, or 4-segmented, or 5-segmented; pentamerous, or tetramerous, or trimerous; 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; with an empodium between them (this with no more than two setae). Hind tarsi with as many segments as the mid-tarsi, or with one segment fewer than the mid-tarsi; 3-segmented, or 4-segmented, or 5-segmented.

Elytral length/maximum width across the elytra 0.57–2.75. 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, or glabrous. 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, 6–7, or 6–7 to 10. Scutellary striole absent. Wings well developed, or absent or much reduced. Wings without an anal lobe. Wings without a medial fleck. Abdominal sternites 4–6; 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, or apparently without functional spiracles. The male external genitalia staphylinoid, or not classified (Coloninae).

Adult habitat, ecology. Land-dwellers; in divers habitats, in decaying plant material, in rotting wood, associated with fungi, and on shed fur or feathers (with some species favouring birds’ nests and mammal dens); necrophagous, or consuming decaying plant material, or mycetophagous.

Larvae. Mature larvae minute (less than 3 mm long), or small to medium-sized. The larvae elongate and more or less parallel-sided, or oblong to ovate. Body circular in cross-section, or somewhat flattened. Vestiture restricted to fine hairs or setae, or not restricted to fine hairs or setae. The larvae dorsally heavily pigmented or sclerotized, or dorsally only very lightly pigmented or sclerotized; ventrally more or less heavily pigmented, or ventrally only very lightly pigmented. The antennae 3 segmented, or 4 segmented. Stemmata present; on either side of the larval head when present, 1–3, 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 with a single lobe or tooth, or bilobed or bidentate. 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 entirely dorsal. 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 presumably not predacious; in decaying plant material, in rotting wood, associated with fungi, and in shed fur or feathers; consuming decaying plant material and mycetophagous.

Classification. Suborder Polyphaga; Infraorder Staphyliniformia; Superfamily Staphilinoidea.

Representation in Britain and Ireland, and worldwide. About 3800 species worldwide; genera at least 13 (?). 92 species in Britain; genera in Britain 20; Agathidium, Catops, Colon, Leiodes, etc. E.g., Catops morio (Dissembling Catops); Leiodes cinnamomea (Truffle Beetle).

Illustrations. • Catops morio (Dissembling Catops: B. Ent. 566). • Leiodes cinnamomea (Truffle-beetle: B. Ent. 251). • Leiodes cinnamomea (details, B. Ent. 251). • Leiodes cinnamomea: B. Ent. 251, legend+text. • Leiodes cinnamomea: B. Ent. 251, text cont.. • Agathidium (5 spp.), Amphicyllis globus and Anisotoma (as Liodes, 3 spp.): with Clambidae and Leptinidae, Fowler 3, 71 (1889). • Fowler 3, 71 (1889): original legend.. • Leiodes (8 spp.), Colenis immunda, Agaricophagus cephalotes, and Hydnobius (3 spp.): Fowler 3, 72 (1889). • Fowler 3, 72 (1889): original legend.. • Agathidium badium, Catops (2 spp.), Leiodes (8 spp.), Ptomaphagus sericatus medius: Fowler Suppl. 10, 1913. • Fowler Suppl. 10, 1913: original legend.. • Catops (5 spp.), Choleva, Colon (3 spp.), Parabathyscia, Ptomaphagus, Sciodrepoides (with Sphaeritidae): Fowler 3, 75 (1889). • Fowler 3, 75 (1889): original legend.. • Choleva (2 spp.) and Nargus (3 spp.), with Silphidae: Fowler 3, 74 (1889). • Fowler 3, 74 (1889): original legend.. • Colon (6 spp.), with Scydmaenidae: Fowler 6, 11 (1913). • Fowler Suppl. 11, 1913: 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.’.