British insects: the families of Coleoptera
British insects: the families of Coleoptera | |
~ Hylophilidae, Xylophilidae.
General appearance. 1.5–2 mm long. Body length/maximum body width 1.4–3.1. Elytral length/pronotal length 2.7–5.2. 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 elongate-oval; conspicuously necked; somewhat waisted to conspicuously waisted; entirely reddish, or with head and thorax black. Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. Beetles not prognathous. Inclination of the head strong. Eyes strongly protuberant, or not strongly protuberant; accommodating the antennae in an anterior notch; bristly, or without bristles; coarsely facetted (granulated). Ocelli absent. Antennae about half the insect's head to tail length to long, but not exceeding the insect’s head to tail length; 11 segmented; hairy. Antennal scape not swollen. Antennae filiform. Antennal insertions visible from above. Prothorax about as long as wide. Pronotal length/maximum pronotal width 0.4–1.2. 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. Hind coxae not shaped posteriorly to receive the femur. Tarsal segmentation formula 4, 4, 4, or 4, 4, 3. The tarsi exhibiting bilobed segments (weakly), or without bilobed segments (lobed beneath only); those of the front and middle legs, and sometimes of the hind legs with a tiny penultimate segment hidden by distal lobing of the fourth and fused to the fifth (in all the legs the basal segment is very long, the antepenultimate one is lobed beneath, and the penultimate one is very small). Front tarsi with as many segments as the mid-tarsi; 5-segmented. Mid-leg tarsi 5-segmented; pseudotetramerous. The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi simple. 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 1.15–2.52. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite. Scutellary striole absent. Wings well developed. Exposed abdominal sternites 4–5; comprising both fused and movable components; immovably joined 2 (the two basal sternites immovable). Abdominal segment 8 apparently without functional spiracles.
Adult habitat, ecology. Predacious, or not predacious (?); in living vegetation, or in rotting wood (usually found in or near old wood, or under leaves of trees and shrubs).
Larvae. Larvae predacious, or not predacious (?); in rotting wood.
Classification. Suborder Polyphaga; Infraorder Cucujiformia; Superfamily Tenebrionoidea.
Worldwide and British representation. About 1000 species worldwide; genera about 50 (mostly tropical). 3 species in Britain; genera in Britain 1; Aderus. E.g., A. oculatus (Fly-headed Beetle).
General comments. Very small beetles resembling Anthicidae; head deflexed, sharply constricted behind the eyes; body pubescent, yellowish or brown. Tarsal segment numbers in published descriptions differ, presumably owing to occurence of tiny inconspicuous components: cf. Curtis’s illustration..
Illustrations. • Aderus oculatus (Fly-headed beetle): B. Ent. 299. • Aderus oculatus: B. Ent. 299, (details). • Aderus oculatus: B. Ent. 299, legend+text. • Aderus oculatus: B. Ent. 299, text, cont.. • Aderus oculatus and Aderus populneus (as Xylophilus), with Anthicus and Meloïdae: Fowler 5, 151 (1891). • Fowler 5, 151 (1891): 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’.
