Cross-breeding experiments with Argas (Persicargas) persicus, A. (P.) arboreus and A. (P.) walkerae showed unequivocally the validity of these 3 Persicargas spp., because, in spite of copulation and independent of the sexual partnership, interspecific crossings never resulted in reproductive progenies. In a few cases only a small number of eggs were laid, which, however, never embryonated even
... [Show full abstract] after incubation for 4 months in optimum abiotic conditions. Therefore, these 3 Persicargas spp. are to define on principle as unequivocally demarcated and real biological units, which are separated by sexual isolation and accordingly represent valid species.