British insects: the families of Coleoptera
British insects: the families of Coleoptera |
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Wasps'-nest beetles.
General appearance. 5–17 mm long. Body length/maximum body width 2.25–4.75. Elytral length/pronotal length 0.9–5. 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, or distinctly narrower than greatest elytral width. Beetles elongate (and tapered); dorsally strongly convex (humped); asymmetrically humped, and tapered to the rear; conspicuously necked, or not necked; not waisted to somewhat waisted; brown or black, sometimes patterned with a yellow or brown and black 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. Inclination of the head slight to strong. Eyes strongly protuberant, or not strongly protuberant; bristly, or without bristles. Antennae short; 2–4 segmented, or (9–)11 segmented. Antennal scape not swollen. Antennae pectinate (or plumose). Antennal insertions visible from above, or hidden from above; not in fossae. Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.25–1.42. Prothorax without notopleural sutures. Metaventrite without a transverse groove. Fore coxal cavites closed behind. Hind coxae not shaped posteriorly to receive the femur. Tarsal segmentation formula 5, 5, 4. The tarsi without bilobed segments; without ‘hidden’ segments. Front tarsi with as many segments as the mid-tarsi; 5-segmented. Mid-leg tarsi 5-segmented; pentamerous. The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi simple, or one-toothed or bifid, or serrate, denticulate or pectinate; with an empodium between them (this sometimes with three or more setae), or without an associated empodium. Hind tarsi with one segment fewer than the mid-tarsi; 4-segmented. Elytra present. Elytral length/maximum width across the elytra 0.55–3.3. Elytra individually distinctly tapered to their apices; not meeting along the full length of the mid-line; short, exposing several terminal abdominal tergites; exposing at least three complete abdominal tergites; not truncate. Scutellary striole absent. Wings well developed, or absent or much reduced; fringed with long hairs on the hind margin, or not fringed. Exposed abdominal sternites 5–9; all articulated and movable. Abdominal segment 8 apparently without functional spiracles.
Adult habitat, ecology. Predacious, or not predacious (?); in living vegetation (free living, commonly found in flowers).
Larvae. Larvae predacious (or rather endoparasitic, on wasp larvae); in wasps' nests. The larva active, heavily sclerotized, elongate-oval, with many ocelli and long 2- or 3-segmented antennae.
Classification. Suborder Polyphaga; Infraorder Cucujiformia; Superfamily Tenebrionoidea.
Worldwide and British representation. About 450 species worldwide. 1 species in Britain (M. paradoxus (Wasps' Nest Beetle)); genera in Britain 1; Metoecus.
General comments. The beetles humped and tapered, with deflexed head.
Illustrations. • Metoecus paradoxus (Wasps'-nest beetle: B. Ent. 019). • Metoecus paradoxus (details, B. Ent. 019). • Metoecus paradoxus: B. Ent. 019, legend+text. • Metoecus paradoxus: B. Ent. 019, text cont.. • Metoecus paradoxus, with Anthicidae and Anaspis: Fowler 5, 150 (1891). • Fowler 5, 150 (1891): original legend.. • Metoecus paradoxus (Rye & Fowler X6).
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’.
