Insects of Britain and Ireland: the families of Coleoptera
General appearance. 1.1–6 mm long. Body length/maximum body width 1.3–3. Elytral length/pronotal length 2.32–4. 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 broadly oval to elongate; not necked; not waisted to somewhat waisted; brown or dark brown, sometimes with orange markings; exhibiting bright warning colours, or without warning colouration. Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. Eyes strongly protuberant; bristly, or without bristles; coarsely facetted. 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. The mandibular apices 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. The apical segment of the maxillary palps cylindrical to fusiform, or somewhat expanded and truncate to subtriangular. The apical segment of the labial palps not expanded apically. Antennae short; 11 segmented. Antennal scape swollen, or not swollen (?). Antennae gradually expanding towards the apex to clubbed. Antennal clubs 2 segmented, or 3 segmented. Antennal insertions visible from above, or hidden from above.
Cervical sclerites present. Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.38–0.91. 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; elevated above the mesoscutum in lateral view; anteriorly simple; posteriorly broadly rounded or obtusely angulate, or truncate. The prosternal process complete; slightly overlapping 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; narrowly separated, or quite widely separated; slightly transverse, or circular to longer than wide; with narrow lateral extensions, or without lateral extensions; internally closed by a slender bar. The mid-leg coxae countersunk in mesocoxal cavities; separated by less than the shortest diameter of the cavity. The mid-leg coxal cavities narrowly separated; not or scarcely oblique; open laterally. Hind-leg coxae contiguous or narrowly separated; not markedly extended laterally; not shaped posteriorly to receive the femur. Tarsal segmentation formula 4, 4, 4. The tarsi without bilobed segments; without hidden segments (but the first and fourth segments longer than the second and third). Front tarsi with as many segments as the mid-tarsi, or with one segment fewer than the mid-tarsi; 3-segmented (sometimes, in males), or 4-segmented. Mid-leg tarsi 3-segmented, or 4-segmented; 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, or one-toothed or bifid. Hind tarsi with as many segments as the mid-tarsi; 3-segmented, or 4-segmented.
Elytral length/maximum width across the elytra 1.16–1.97. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite; smooth; non-glabrous (with semi-erect pubescence); finely punctate- striate. 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 more than five, 10, or 11. Scutellary striole absent. Elytra with epipleura. Elytral epipleura falling short of the elytral tips. Wings well developed, or absent or much reduced; fringed with long hairs on the hind margin. Wings without an anal lobe. Wings with a medial fleck, or without a medial fleck; the medial fleck if present, not bisected by a vein. Abdominal tergites 9. Abdominal sternites 5; all articulated and moveable. Abdominal segment 8 apparently without functional spiracles. The male external genitalia tenebrionoid.
Adult habitat, ecology. Land-dwellers; in decaying plant material, in rotting wood, associated with fungi, and in stored plant products (in mouldy materials); mycetophagous.
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 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 4, 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 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, annular-uniforous or annular-biforous); without spiracular tubes. The abdominal apex without a respiratory chamber. Abdominal tergum 8 without amature. The last abdominal segment with cerci.
Larvae in decaying plant material, in rotting wood, associated with fungi, and in stored plant products; phytophagous, or consuming decaying plant material, or eating dried plant material or stored plant products, or mycetophagous (mostly associated with moulds and rotting fungal fruit bodies, with species of Litargus and Typhaea ocurring in stored products, but some family members feed on pollen).
The larvae subcylindrical with well developed legs, the exserted head with 4 to 6 pairs of ocelli, the abdomen 9-segmented.
Classification. Suborder Polyphaga; Infraorder Cucujiformia; Superfamily Tenebrionoidea.
Representation in Britain and Ireland, and worldwide. About 200 species worldwide; genera 18. 12 species in Britain; genera in Britain 5; Litargus, Mycetophagus, Pseudotriphyllus, Triphyllus, Typhaea. E.g., Mycetophagus piceus (Orange-spotted Fungus-eater); Mycetophagus multipunctatus; Typhaea stercorea.
General comments. Very small, broadly ovate, brown or dark brown beetles with semi-erect pubescence. The antennae sometimes borne on raised tubercles.
Illustrations. • Mycetophagus piceus (Orange-spotted Fungus-eater: B. Ent. 156). • Mycetaphagus piceus: B. Ent. 156, legend+text. • Mycetaphagus piceus: B. Ent. 156, text cont.. • Mycetaphagus piceus (Janson 97). • Mycetophagus multipunctatus (Rye & Fowler VII2). • Typhaea stercorea: B. Ent. 702. • Typhaea stercorea: B. Ent. 702, legend+text. • Typhaea stercorea: B. Ent. 702, text cont.. • Litargus connexus, Mycetophagus (6 spp.), Triphyllus bicolor (with Dermestidae): Fowler 3, 96 (1889). • Fowler 3, 96 (1889): original legend.. • Typhaea stercorea, with Cryptophagidae and Scaphidiidae: Fowler 3, 95 (1889). • Fowler 3, 95 (1889): original legend.. • Typhaea stercorea (Janson 98).
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’.