British Insects: the Families of Coleoptera
British Insects: the Families of Coleoptera |
|
~ Dascillidaes. lat., including Eubriidae, Psephenoididae.
General appearance. 1.5–2 mm long. Body length/maximum body width 1.35–1.77. Elytral length/pronotal length 2.8–4.57. 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 oval; dorsally strongly convex; not necked; not waisted; black or dark brown. Upper surfaces of body non-glabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. Inclination of the head slight to strong. Eyes strongly protuberant; without bristles; finely facetted. Antennae long, but not exceeding the insect’s head to tail length; 11 segmented. Antennal scape not swollen. Antennae finely serrate. Mandibular prosthecae absent.
Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.3–0.55. Prothorax at its widest not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Metaventrite with a transverse groove. 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. Front tarsi with as many segments as the mid-tarsi; 5-segmented. Hind tarsi with as many segments as the mid-tarsi; 5-segmented. Tarsal claws simple, or one-toothed or bifid. Elytral length/maximum width across the elytra 1.05–1.38. Elytra exposing no more than part of the terminal tergite; hard. Scutellary striole present, or absent. Elytra non-glabrous (shortly, finely and densely hairy). Wings well developed.
Visible abdominal sternites 5–6; immovably joined 3. Abdominal segment 8 apparently without functional spiracles.
Habitat, ecology. Water-beetles to land-dwellers (or sub-aquatic: found in moist places, sometimes in water); moving in the water by alternate, walking leg movements.
General comments. The elytra deeply furrowed.
Larvae. Larvae aquatic (found clinging to stones).
Classification. Suborder Polyphaga; Superfamily Dryopoidea.
British representation. Genera 1; 1 species.
Illustrations. • Eubria palustris (from Joy). Limnichus pygmaeus (Limnichidae). Eubria palustris (Psephenidae).
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’.
