British insects: the families of Coleoptera
British insects: the families of Coleoptera | |
Melasidae, ~Elateridae.
False Click-beetles.
General appearance. 2.8–30 mm long (?). Body length/maximum body width 2.4–3.6. Elytral length/pronotal length 2.35–4.85. 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 elongate to slender; not necked; not waisted. Upper surfaces of body non-glabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. Beetles not clicking and ‘jumping’ (the clicking mechanism apparently non-functional). Inclination of the head slight to very strong. Eyes strongly protuberant, or not strongly protuberant; without bristles; finely facetted. The frons with a transverse ridge between the eyes. The labrum not externally apparent. Antennae very short to short; 11 segmented. Antennal scape not swollen. Antennae filiform, or serrate, or pectinate. Antennal insertions visible from above, or hidden from above; ‘countersunk’ within saucer-like fossae, or not in fossae. Mandibular prosthecae absent. Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.48–1. Prothorax without notopleural sutures. Metaventrite without a transverse groove. Hind coxae contiguous, posteriorly shaped to receive the retracted femur (with transverse cavities). Tarsal segmentation formula 5, 5, 5. 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 (but sometimes with basal setae). The claws of the mid-leg tarsi simple, or one-toothed or bifid, or serrate, denticulate or pectinate; 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; 5-segmented. Elytral length/maximum width across the elytra 1.7–3. Elytra exposing no more than part of the terminal tergite; hard. Scutellary striole absent. Elytra non-glabrous. Wings well developed. Exposed abdominal sternites 5; all fused and immovable; immovably joined 5 (sternite 5 not movable on 4). Abdominal segment 8 with apparently functional spiracles.
Adult habitat, ecology. Not predacious (?); in living vegetation.
Larvae. Larvae predacious and not predacious (?); in decaying plant material (or in the soil), or in rotting wood, or in or under bark. The small-headed, legless larvae have greatly reduced mouthparts with mandibles biting outwardly as in Throscidae, very small antennae, and a subcylindric 9-segmented abdomen.
Classification. Suborder Polyphaga; Infraorder Elateriformia; Superfamily Elateroidea.
Worldwide and British representation. About 1700 species worldwide. 6 species in Britain; genera in Britain 5; Dirhagus, Epiphanis, Eucnemis, Hylis, Melasis. E.g., Melasis buprestoides (Buprestis-like Melasis).
General comments. The adult prothorax (the first segment of the thorax) and the mesothorax (the second segment) are freely movable on one another, and the prosternal extension resembles that in Elateridae (q.v.), but the ‘clicking mechanism’ is apparently non-functional in this family. The labrum is not visible when the adults are viewed from above..
Illustrations. • Melasis buprestoides (Buprestis-like Melasis: B. Ent. 055). • Melasis buprestoides (details, B. Ent. 055). • Melasis buprestoides: B. Ent. 055, legend+text. • Melasis buprestoides: B. Ent. 055, text cont.. • Eucnemus capucina and Melasis buprestoides (with Buprestidae, etc.): Fowler 4, 104 (1890). • Fowler 4, 104 (1890): original legend. • Dirhagus pygmaeus, with Elateridae: Fowler 4, 105 (1890).
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’.
