British insects: the families of Coleoptera
British insects: the families of Coleoptera |
|
Including Phaenocephalidae.
Shining Flower-beetles.
General appearance. 1.5–3 mm long. Body length/maximum body width 1.15–1.93. Elytral length/pronotal length 2.6–3.85. 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, or distinctly narrower than greatest elytral width. Beetles broadly oval; terrapin-like in shape, with flattened and clear margins to thorax and elytra; dorsally dorsally strongly convex (but flat beneath); not necked; not waisted; decidedly short-legged. Upper surfaces of body glabrous or subglabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. Beetles not prognathous. Eyes not strongly protuberant; without bristles. Antennae short to long, but not exceeding the insect’s head to tail length; 11 segmented; without a much-elongated scape. Antennal scape swollen (enlarged and triangular). Antennae clubbed. Antennal clubs 3 segmented. Antennal insertions visible from above, or hidden from above. Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.26–0.5. Prothorax at its widest not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Metaventrite without a transverse groove. Hind coxae not shaped posteriorly to receive the femur. Tarsal segmentation formula 4, 4, 4. The tarsi exhibiting bilobed segments; with a tiny penultimate segment hidden by distal lobing of the fourth and fused to the fifth, or without ‘hidden’ segments (segment four greatly reduced, the first three broad and lobed below). Front tarsi with as many segments as the mid-tarsi; 4-segmented, or 5-segmented. Mid-leg tarsi 4-segmented, or 5-segmented; pentamerous, or tetramerous. The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi one-toothed or bifid (appendiculate, or with a basal tooth). 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 0.9–1.5. Elytra exposing no more than part of the terminal tergite; hard; very glossy; striate, or without striae (but usually with distinct sutural striae towards the rear). Scutellary striole absent. Elytra glabrous; with epipleura. Elytral epipleura reaching to the tips of the elytra. Wings well developed, or absent or much reduced. Exposed abdominal sternites 5; all articulated and movable. Abdominal segment 8 apparently without functional spiracles.
Adult habitat, ecology. Not predacious; phytophagous and mycetophagous (eating pollen and smuts); in living vegetation and associated with fungi (commonly in flowers, especially compositae).
Larvae. Larvae not predacious; phytophagous and mycetophagous (commonly in flowers, especially Compositae, eating pollen and smuts); commonly on living vegetation. The larvae rather onisciform, whitish, with 3-segmented antennae, 2 to 5 pairs of ocelli on each side and well developed legs; abdomen 9-segmented.
Classification. Suborder Polyphaga; Superfamily Cucujoidea.
Worldwide and British representation. About 640 species worldwide; genera about 50. 16 species in Britain; genera in Britain 3; Olibrus, Phalacrus, Stilbus.
General comments. Very small, broadly oval and strongly convex beetles, the surface glabrous and polished.
Illustrations. • Olibrus aeneus, Phalacrus corruscus, Stilbus testaceus (with Coccinellidae): Fowler 3, 81 (1889). • Fowler 3, 81 (1889): original legend.. • Olibrus flavicornis (with Coccinellidae, Pselaphidae, etc.): Fowler Suppl. 12, 1913. • Fowler Suppl. 12, 1913: original legend.. • Olibrus, Phalacrus, Stilbus (from Joy).
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’.
