Revision of first instar larvae of Meloe, subgenera Eurymeloe and Coelomeloe, with new descriptions and a key to the species (Coleoptera: Meloidae)

In this paper the larval morphology of the Palaearctic Meloe subgenera Eurymeloe and Coelomeloe is revised. We describe the first instar larva of Meloe (Eurymeloe) apenninicus, endemic to the Italian peninsula and, comparatively, triungulins of three more species of the subgenus Eurymeloe: M. apivorus, M. ganglbaueri, misidentified in literature, and of M. mediterraneus, incompletely described. Descriptions are accompanied by scanning electron microscope (SEM) photos of diagnostic characters and by a table reporting the size of the morphological details of 11 Euro-Mediterranean species and of M. (Coelomeloe) tuccius. The taxonomic position of the subgenus Coelomeloe and its distinction from Eurymeloe are discussed on the basis of larval morphology. Taxonomical problems concerning some Eurymeloe species are also discussed. A key to first instar larvae of all known Eurymeloe and Coelomeloe triungulins is provided.