The pine processionary moth, Thaumetopoea pityocampa , is an iconic insect in the Mediterranean culture because of its economic and medical importance and the unique traits of the life history, namely the winter feeding and the construction of conspicuous silk tents by the larvae. Its taxonomic status, however, is unclear because the type material is not available and there is confusion among the several species and subspecies described in the last centuries. In the present study, a metadata analysis of morphological and molecular data of the species in the T. pityocampa complex were considered for species delimitation, using more than 400 individuals from more than 120 geographic locations. A reconstruction of the origin of the material used for the first formal description has allowed to identify the type locality and to design a neotype. In addition, as Denis and Schiffermüller were referring to the work of Réaumur for details about the species, the description provided by Réaumur was reviewed. The results indicate that the barcode region of mitochondrial DNA is a reliable trait to separate species in most cases whereas morphological traits are not. Hybridization among taxa makes it difficult to delimit species in contact zones when mating barriers are not present. In other cases, such as the populations of Crete Island, the lack of gene flow with the mainland population may support species delimitation even when morphological traits are not conclusive. Thus, the new species Thaumetopoea cretensis is described here based on the evidence obtained from a previous study. Species delimitation based on both mitochondrial and nuclear markers allowed maintenance of three species of the complex ( T. cretensis , T. pityocampa , and T. wilkinsoni ) while more data are needed to determine the status of two recently described species: T. hellenica and T. mediterranea .