British insects: the families of Coleoptera
British insects: the families of Coleoptera | |
Including Dacnidae.
Pleasing Fungus-beetles.
General appearance. 2.5–7 mm long. Body length/maximum body width 1.15–2.87. Elytral length/pronotal length 2–5.75. Base of prothorax not or scarcely narrower than the combined elytral bases. Greatest prothoracic width not narrower or only slightly narrower than the greatest elytral width. Beetles oval to elongate; convex beneath; not necked; not waisted to somewhat waisted; often with a bright yellow and black pattern, or metallic colour; 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; with neither scales nor scale-like setae.
Detailed morphology. Beetles without a rostrum; prognathous. Inclination of the head slight. Eyes strongly protuberant, or not strongly protuberant; bristly, or without bristles. Antennae short; 11 segmented. Antennal scape not swollen. Antennae clubbed. Antennal clubs 3 segmented (flattened). Antennal insertions visible from above, or hidden from above; not in fossae. Mandibular prosthecae well developed, or absent. Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.25–0.97. Prothorax at its widest not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Metaventrite without a transverse groove. Fore coxal cavites open behind. Hind coxae not shaped posteriorly to receive the femur. Tarsal segmentation formula 5, 5, 5, or 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 (but the fourth segment usually small). Front tarsi with as many segments as the mid-tarsi; 5-segmented. Mid-leg tarsi 5-segmented; pentamerous, or pseudotetramerous. The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi simple; without an associated empodium. Hind tarsi with as many segments as the mid-tarsi, or with one segment fewer than the mid-tarsi; 4-segmented, or 5-segmented. Elytral length/maximum width across the elytra 1–2.2. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite. Scutellary striole present, or absent. Elytra non-glabrous, or glabrous; with epipleura. Elytral epipleura reaching to the tips of the elytra. Wings well developed, or absent or much reduced. Exposed abdominal sternites 5; all articulated and movable, or comprising both fused and movable components; immovably joined when present, 2. Abdominal segment 8 apparently without functional spiracles.
Adult habitat, ecology. Not predacious; under bark and associated with fungi (on trees).
Larvae. Larvae not predacious; mycetophagous (on fleshy fungi); in or under bark and in fungi (on trees). The larvae subcylindric, whitish to pale brown, with well developed legs and segmental sclerites bearing spines; head hypognathous with 5 or 6 pairs of ocelli and long, 3-segmented antennae.
Classification. Suborder Polyphaga; Superfamily Cucujoidea.
Worldwide and British representation. Genera at least 100. 7 species in Britain; genera in Britain 3; Dacne, Triplax, Tritoma. E.g., Tritoma bipustulata.
General comments. Ovoid or elongate beetles associated with fungi, the tibiae flattened and expanded.
Illustrations. • Triplax aenea: B. Ent. 706. • Triplax aenea: B. Ent. 706, legend+text. • Triplax aenea: B. Ent. 706, text cont.. • Tritoma bipustulata (Double-spotted Tritoma: B. Ent. 498). • Tritoma bipustulata (details, B. Ent. 498). • Tritoma bipustula: B. Ent. 498, legend+text. • Tritoma bipustula: B. Ent. 498, text cont.. • Tritoma bipustulata (Rye & Fowler XV4). • Dacne bipustulata and D. rufifrons, with Coccinellidae and Endomychidae: Fowler 3, 83 (1889). • Fowler 3, 83 (1889): original legend.. • Triplax aenea, T. russica,, and Tritoma bipustulata (with Colydiidae): Fowler 3, 84 (1889). • Fowler 3, 84 (1889): original legend.. • Triplax lacordairii and T. scutellaris, with unrelated taxa: Fowler Suppl. 12, 1913. • Fowler Suppl. 12, 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. British insects: the families of Coleoptera. Version: 2nd January 2012. http://delta-intkey.com’.
