Abstract Cratomorphus Motschulsky, 1853 includes 38 species restricted to the Neotropical region. Based on adult males from Mexico, Cratomorphus leoneli sp. nov. is herein described from the states of Oaxaca, Campeche and Chiapas. We place the new species in Cratomorphus’ group IV, which includes species with the posterior border of sternite VIII medially produced. The new species can be distinguished from other species of the group IV by the clypeus subquadrate, posterior margin of pygidium bisinuate and posterior margin of sternite VIII with an apically obtuse median projection. Illustrations of habiti and diagnostic traits are provided, along with an identification key and a distribution map for the group IV species.

Resumen Cratomorphus Motschulsky, 1853 incluye 38 especies restringidas a la región Neotropical. Con base en machos adultos de México, se describe Cratomorphus leoneli sp. nov., distribuida en los estados de Oaxaca, Campeche y Chiapas. Incluimos a la nueva especie en el grupo IV de Cratomorphus, que incluye especies con el borde posterior del esternito VIII proyectada medialmente. La nueva especie se puede distinguir de otras del grupo IV por el clípeo subcuadrado, pygidium con margen posterior bisinuado y esternito VIII con un margen posterior con una proyección mediana apicalmente obtusa. Se proporcionan ilustraciones del hábito y caracteres diagnósticos, junto con una clave de identificación y un mapa de distribución de los machos de las especies del grupo IV.

Abstract Lycidae are among the better studied groups in the superfamily Elateroidea, however despite the progress in the taxonomic understanding of the Neotropical fauna, much still remains unknown and undescribed in the region. The description of the new genus Xenolycus gen. nov., from Serra dos Órgãos, a subrange of the Serra do Mar mountain range, in the Atlantic Rainforest in Rio de Janeiro State, Brazil, contributes to the knowledge of the Neotropical Lycidae fauna. The new genus can be distinguished from all other known Calopterini and Neotropical Lycidae by the combination of a pronotum with a wide, deep and strongly visible longitudinal cell in the disc area, the filiform antennae, the dehiscent elytra with reticulation strongly reduced and bearing only two weakly developed elytral costae and the mouthparts partially reduced, with rudimentary, barely visible mandibles. The type species, Xenolycus costae sp. nov., is illustrated and diagnostic characters and a discussion on the tribal placement of the new genus are provided.

RESUMO Cladodes illigeri (Kirby, 1818) é redescrito, o qual pode ser diagnosticado pelos seguintes caracteres: padrão do colorido negro, com par de faixas amarelo-pálidas nas margens elitrais; pigídio bisinuoso, ângulos posteriores arredondados, tão longo quanto a margem mediana; e edeago com falo 1/3 mais curto que os parâmeros, os quais são sinuosos apicalmente. Cladodes lamellicornis (Motschulsky, 1854) é sinonimizado com C. illigeri. Novos registros da Mata Atlântica e ilustrações das características estruturais são fornecidos.

ABSTRACT Cladodes illigeri (Kirby, 1818) is redescribed, and can be distinguished by the following features: color pattern overall black, paired spots and elytral margins pale yellow; pygidium bisinuate, posterior angles rounded, as long as median margin; and aedeagus with phallus 1/3 shorter than the parameres, which are sinuated apically. Cladodes lamellicornis (Motschulsky, 1854) is proposed as a junior synomym of C. illigeri. New records from the Atlantic Rainforest and illustrations for structural features are provided.