Description

Adults are glabrous and shiny, most species are brightly coloured and many are patterned and/or metallic; it really is worth seeing some of these e.g. the South African Lema trilineata Olivier, 1808, ‘the tobacco slug’, is yellow with longitudinal dark stripes to the suture and lateral margins, and the southeast Asian Lilioceris adonis (Baly, 1859) and L. major (Pic, 1916) are striking. Most are medium sized, 4-8mm although some Oulema are tiny, around 1.5mm, and some Lilioceris up to 14mm. Females are generally larger than males. All have a characteristic form; from above the head is transverse, and the pronotum is narrower than the parallel-sided elytra. Head prognathous and about as wide as the pronotum, with temples constricted behind convex and prominent eyes so forming a distinct neck. Vertex generally convex, variously punctured and microsculptured, separated from the eyes by an oblique depression and often with a median longitudinal impression. Eyes entire to weakly, in Oulema, or strongly, in Lema, emarginate. Antennal insertions widely separated, much more so than the length of the basal segment, and visible from above. Antennae 11-segmented and filiform or widened towards the apex, and generally with the basal segments shorter than the others. Frontoclypeal suture absent, clypeus and labrum distinct; the labrum transverse and truncate. Mandibles short and curved, bidentate to multi-dentate and variously toothed internally. Apical segment of the maxillary and labial palpi cylindrical and narrowed towards the apex. Pronotum quadrate to slightly transverse and constricted across the middle or towards the base, giving a pinched appearance from above, parallel-sided to widest at the base, anterior angles distinct to simply rounded, posterior angles distinct and often acute. Posterior margin often strongly bordered, lateral and anterior margins simple. The surface is usually sparsely and finely punctured although sometimes with shallow depressions e.g. in some Pseudocriocerus. Prosternum short in front of round coxal cavities, the process narrow and acute; not expanded posterior to the coxae. Mesocoxal cavities round and narrowly separated, metacoxal cavities transverse but not extended to reach the elytral epipleura, narrowly to widely separated. Scutellum visible; triangular to rounded and sometimes raised. Elytra elongate and flattened, completely covering the abdomen and continuously rounded apically, parallel-sided to rather strongly constricted at, or in front of, the middle, with prominent shoulders and very narrow explanate margins. Each with 9 or 10 rows of punctures and in some with a scutellary row, in a very few e.g. the Central American Metapoceris alternans (Lacordaire, 1845) with variously developed longitudinal carinae. Hind wings well-developed and most species are good fliers. Abdomen with five visible ventrites, the first more than twice the length of the second and lacking post-coxal lines. In males segments 2-4 have tufts of setae. Legs well-developed and proportionally long, the base of the femora sometimes touch the coxae due to the strongly oblique trocanter/femora joint. Femora generally weakly thickened although in the Neotropical genus Neolema they may be broadly dilated. In some species there are large spines or rows of small teeth on the posterior margin. Tibiae generally slender and smooth along the external margin although the metatibiae have small basal or medial spurs. Tarsi 5-segmented with the third bilobed and the fourth reduced, so appearing tetramerous. The basal segment is longer than the second, and 1-3 have a dense ventral clothing of adhesive setae. Claws free in Criocerini, or connate in Lemiini, empodium very reduced, often not visible.