Description

All are very convex and rather globular beetles, superficially resembling Agathidium Panzer, 1797 (Leiodidae, Agathidiini), but have a distinctive, compact 3-segmented antennal club, or Clambidae but are distinctive in head and tarsal structure. They are broadly elongate to almost round and more-or-less continuous in outline, although this is broken when specimens are laid out for setting, and they can roll into a compact ball (conglobulation) with the head held ventrally so that the mandibles are resting against the metasternum. The head is transverse and proportionally very large though not so wide as the pronotum, with entire and very large eyes that follow the outline (Cybocephalus means ‘cube head’), the vertex is convex and smooth, without sculpture, the temples short and hidden under the pronotum; generally rather parallel but sometimes strongly converging towards the base from a small tooth behind the eyes, the clypeus smooth and extended in front of the eyes, without a distinct frontoclypeal suture. Antennae inserted laterally in front of the eyes, the insertions widely separated; 10- or 11-segmented, segments 1 and 2 large and globular, 3 to 7 or 8 quadrate to slightly elongate, and the club 3-segmented, compact and gradually thickened, the penultimate segment is sometimes wider than the terminal segment which is truncate or widely curved apically. Ventrally the head lacks grooves for the reception of the antennae, a feature present in Nitidulids. Pronotum widely transverse and convex, smooth and very finely punctured and pubescent, any microsculpture being weakly impressed or defined and visible only at high magnification. The lateral margins are strongly curved and finely bordered, the anterior and posterior angles rounded and the basal margin weakly sinuate. The scutellum is generally proportionally large, triangular and sometimes widely transverse. Procoxae round and protruding (transverse in Nitidulids), the Prosternal process not extending beyond the basal margin of the cavities, as it does in Nitidulids, and without mesoventral procoxal rests which are present in Nitidulids. The elytra are smoothly rounded and very convex, completely covering the abdomen and lacking striae although in some there may be a longitudinal impression parallel to the suture towards the base, the surface is generally very finely and sparsely punctured and pubescent although in some Cybocephalus these become much stronger behind the middle. In some cases the elytra are weakly truncate or widely curved around the apex, and in some e.g. C. metallicus Baudi, 1870, they diverge weakly behind the middle. Abdomen with 5 visible sternites, in Nitidulids there are 6. The legs are usually long and slender with the tibiae thin and curved but in some specialized groups e.g. Enrodiellus they are variously dilated and flattened. Tarsi 4-4-4; when the group was originally described they were thought to be 5-5-5, and this justified their inclusion in the Nitidulidae.

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All species are predators and most are specialized both as adults and larvae to feed on scale insects, although if necessary they will predate eggs and young larvae or nymphs of other small insects but in all the species studied it seems that they need to consume scale insects in order to complete their development. Various species are among the most important biological control agents of scale insects on a very wide range of crops e.g. orchard fruits, olives, mangos and pistachio nuts.

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The family is included in the British list on the strength of a single record of the widespread European Cybocephalus fodori Enrödy-Younga, 1965 from Betula pendula in Putney, London in 2000.