British Insects: the Families of Coleoptera
British Insects: the Families of Coleoptera |
|
= Horiidae, including Tetraonychidae.
Oil Beetles, Blister-beetles.
General appearance. 7–32 mm long. Body length/maximum body width 1.1–7. Elytral length/pronotal length 0.4–5.4. 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 oval to elongate; not asymmetrically humped and tapered; abruptly conspicuously necked; somewhat waisted to conspicuously waisted (expanded at the distal part of the abdomen, rather than waisted); reddish yellow, or greenish-, violet- or bluish-black. 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 prognathous, or not prognathous. Inclination of the head slight to very strong. Eyes strongly protuberant, or not strongly protuberant; without bristles. Antennae short to about half the insect's head to tail length; 6–11 segmented. Antennal scape not swollen. Antennae filiform. Antennal insertions visible from above; not in fossae. Mandibular prosthecae well developed to absent.
Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.47–1.6. Prothorax at its widest markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Metaventrite without a transverse groove. Fore coxal cavites closed behind. The tarsi without bilobed segments; without ‘hidden’ segments. Mid-leg tarsi 5-segmented; pentamerous. Claws of the mid-leg tarsi with an appendage, or not appendaged; the appendages when present, not or only lightly sclerotized, or heavily sclerotized, blade-like, or heavily sclerotized, spine-like or bristle-like. Front tarsi with as many segments as the mid-tarsi; 5-segmented. Hind tarsi with one segment fewer than the mid-tarsi; 4-segmented. Tarsal claws simple, or one-toothed or bifid, or serrate, denticulate or pectinate (often with a sclerotized, blade-like process beneath each claw); with an empodium between them (this with no more than two setae), or without an associated empodium. Elytral length/maximum width across the elytra 0.35–3.3. Elytra individually distinctly tapered to their apices to not individually tapered; not meeting along the full length of the mid-line (their apices well separated); covering most of the abdomen, or short, exposing several terminal abdominal tergites (often); exposing no more than part of the terminal tergite to at least three complete abdominal tergites; not truncate; soft. Scutellary striole absent. Wings well developed, or absent or much reduced.
Visible abdominal sternites 5–7; immovably joined 0. Abdominal segment 8 apparently without functional spiracles.
Habitat, ecology. Not predacious; phytophagous; in living vegetation.
General comments. In some overseas species, the maxillae are adapted for absorbing nectar.
Larvae. Larvae predacious; in bees' nests, eating eggs, honey and pollen stores.
Classification. Suborder Polyphaga; Superfamily Cucujoidea.
British representation. Genera 3; 9 species. E.g., Meloë brevicollis (Short-necked Oil-beetle); Apalus muralis (Bees'-nest Beetle).
Illustrations. • Meloë brevicollis (Short-necked Oil-beetle: B. Ent. 279). • Meloë brevicollis (B. Ent. 279, legend+text). • Meloë violacea (Oil-beetle: Giles Watson, photos). • Meloë violacea (Oil-beetle, female depositing eggs: Giles Watson, photos). • Sitaris muralis (Bees’-nest beetle: B. Ent. 340). • Sitaris muralis (details, B. Ent. 340). • Sitaris muralis: B. Ent. 340, legend+text.
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: 9th June 2008. http://delta-intkey.com’.
