Insects of Britain and Ireland: the families of Coleoptera

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L. Watson and M. J. Dallwitz

Nitidulidae

Including Kateretidae; = Cybocephalidae.

Sap beetles.

General appearance. 1.4–8 mm long. Body length/maximum body width 1.2–5.4. Elytral length/pronotal length 1.38–2.75. 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; terrapin-like in shape, with flattened and clear margins to thorax and elytra, or not terrapin-like in shape, and without flattened and clear margins to both thorax and elytra; dorsally flattened; not necked; not waisted to somewhat waisted; decidedly short-legged; brown or black. 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 to very strong. Eyes strongly protuberant, or not strongly protuberant; bristly, or without bristles. The labrum at least partly visible in antero-dorsal view, or concealed beneath the clypeus; labrum if recognized as such, mostly moderately to heavily sclerotized. Mandibles with a well developed mola, or with a reduced mola, or without a mola; with well developed prosthecae to without prosthecae. The mandibular apices variously simple, or bidentate or bilobed, or multidentate or multilobed. The incisor edges of the mandibles simple, or with a single tooth, or with two or more teeth. The maxillae with distinct galea and lacinia apically to the palp (Kateretidae), or with a single apical structure additional to the palp (the rest). The apical segment of the maxillary palps cylindrical to fusiform. The apical segment of the labial palps not expanded apically. Antennae short to longer than the insect's head to tail length; not elbowed; (9–)11 segmented; without a much-elongated scape. Antennal scape swollen. Antennae strongly clubbed. Antennal clubs 3 segmented (transversely). Antennal insertions visible from above, or hidden from above; not in fossae.

Cervical sclerites present, or absent. Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.35–1.18. 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. Scutellum conspicuous; not elevated; anteriorly simple; posteriorly narrowly rounded or acute, or broadly rounded or obtusely angulate. The prosternal process complete; slightly overlapping the mesoventrite, or moderately or strongly 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; narrowly separated to quite widely separated; strongly transverse; with narrow lateral extensions, or without lateral extensions; internally closed by a slender bar, 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 narrowly separated; not or scarcely oblique, or markedly oblique; open laterally (Kateretidae), or closed laterally. Hind-leg coxae variously contiguous or narrowly separated, or widely separated; not markedly extended laterally; not shaped posteriorly to receive the femur. Tarsal segmentation formula 4, 4, 4. The tarsi exhibiting bilobed segments; with a tiny penultimate segment hidden by distal lobing of the fourth and fused to the fifth, or without ‘hidden’ segments. Front tarsi with as many segments as the mid-tarsi; 4-segmented, or 5-segmented. Mid-leg tarsi 4-segmented, or 5-segmented; pentamerous, or pseudotetramerous, or tetramerous; the penultimate segment variously not distinctly shorter than the antepenultimate one, or 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; with an empodium between them (this with no more than two setae), or without an associated empodium. Hind tarsi with as many segments as the mid-tarsi; 4-segmented, or 5-segmented.

Elytral length/maximum width across the elytra 0.68–1.9. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite to at least three complete abdominal tergites; strongly truncate. 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 8 to 11, or 12 or more (some Cryptarchinae only). Scutellary striole absent. Elytra with epipleura. Elytral epipleura falling short of the elytral tips. 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; all articulated and moveable. Abdominal segment 8 apparently without functional spiracles. The male external genitalia cucujiform.

Adult habitat, ecology. Land-dwellers; variously predacious, or not predacious; on living vegetation, or associated with flowers (often in or on them); when non-predatory, phytophagous (often feeding on pollen or nectar, decaying vegetable matter, tree sap or over-ripe fruit), 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 to somewhat flattened, or strongly 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 only very lightly pigmented. The antennae 3 segmented. Stemmata present; on either side of the larval head 2–4. The frontoclypeal suture between frons and clypeus indistinct or absent. The labrum and head capsule separated by a complete suture, or partly fused, with an incomplete suture, or completely fused, with no suture apparent. 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; 1 segmented. Mesothoracic legs present and segmented; 5 segmented; with 1 moveable claw. Visible abdominal segments 10. Tergum 9 of the abdomen entirely dorsal, or entirely dorsal to extending to the underside. The abdomen having functional spiracles on anterior segments (these annular-biforous); with anterior and 8th-segmental spiracles borne at the ends of a series of spiracular tubes, or 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 (a few, e.g. Carpophilus spp. on scale insects), or not predacious (mainly saprophagous); variously in living vegetation and associated with flowers, or in decaying plant material, or associated with fungi, or in carrion; necrophagous, or feeding on dried animal remains, or phytophagous (e.g., Meligethinae inhabiting flowers and eating pollen), or consuming decaying plant material, or mycetophagous (e.g., many consuming spores and fruit bodies of mushrooms, polypores, etc.).

Larvae subcylindrical, white, with small prognathous head.

Classification. Suborder Polyphaga; Superfamily Cucujoidea.

Representation in Britain and Ireland, and worldwide. Genera about 25 (?). 96 species in Britain; genera in Britain 18; Brachypterus and Brachpterolus (Kateretidae), Carpophilus, Cryptarcha, Epuraea, Glischrochilus, Kateretes (Kateretidae), Meligethes, Nitudula, Omostia, etc. E.g., Cryptarcha undulata (Spotted Strongylus); Glischrochilus quadripunctatus (4 Orange-spotted Ips); Soronia punctatissima; Omostia colon.

Illustrations. • Amphotis, Eperua (4 spp.), Nitidula (4 spp.), Omosita (3 spp.): Fowler 3, 88 (1889). • Fowler 3, 88 (1889): original legend.. • Meligethes (10 spp.), Pocadius ferrugineus, Pria dulcamara, Thalycra fervida: Fowler 3, 89 (1889). • Fowler 3, 89 (1889): original legend.. • Cryptarcha, Cychramus, Glischrochilus, Meligethes (6 spp.), Pityophagus: Fowler 3, 90 (1889). • Fowler 3, 90 (1889): original legend.. • Cryptarcha undulata (Spotted Strongylus: B. Ent. 339). • Cryptarcha undulata (details, B. Ent. 339). • Cryptarcha undulata: B. Ent. 339, legend+text. • Cryptarcha undulata: B. Ent. 339, text cont.. • Glischrochilus quadripunctatus (4 Orange-spotted Ips: B. Ent. 306). • Glischrochilus quadripunctatus: B. Ent. 306, legend+text. • Glischrochilus quadripunctatus: B. Ent. 306, text cont.. • Omosita colon: B. Ent.675. • Omosita colon: B. Ent.675, legend+text. • Omosita colon: B. Ent.675, text cont.. • Brachypterus, Carpophilus, Epuraea (5 spp.), Kateretes (with Staphylinidae): Fowler 3, 87 (1889). • Fowler 3, 87 (1889): original legend.. • Carphophilus sexpustulatus, with unrelated taxa: Fowler Suppl. 13, 1913. • Fowler Suppl. 13, 1913: original legend.. • Omosita colon (Janson 86). • Soronia punctatissima (Rye & Fowler VI5).


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’.

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