A Balkan checklist of the millipede genus Megaphyllum Verhoeff, 1894 has been compiled on the basis of literature data, new collections, and reexamination of type and non-type material. Forty-seven species and subspecies are represented in the peninsula, including four species new to science: M. chiosense Lazanyi & Korsos sp. n. from Chios Island, M. cygniforme Lazanyi & Korsos sp. n. from East Macedonia, M. danyii Lazanyi & Korsos sp. n. and M. digitatum Lazanyi & Korsos sp. n. both from the Peloponnese, Greece. The following new synonymies are established: M. monticola (Verhoeff, 1898) syn. n. of M. carniolense (Verhoeff, 1897); M. latesquamosum (Attems, 1903) syn. n. and M. macedonicum (Strasser, 1976) syn. n. of M. montivagum (Verhoeff, 1901). M. species inquirenda is posed from Andros Island, Greece, on the basis of gonopod slide preparations, labeled by Strasser but never published. M. mueggenburgi (Verhoeff, 1901) comb. nov. is suggested, from the genus Cerabrachyiulus Verhoeff, 1901, previously Chromatoiulus Verhoeff, 1894. Species new to the fauna are: M. bosniense (Verhoeff, 1897) new to the fauna of Greece; M. imbecillum (Attems, 1935) and M. montivagum new to the Republic of Macedonia; and M. lictor (Attems, 1904) new to the fauna of Turkey (European part). The following species have been found and localities are published for the first or second time since their original description: M. euphorbiarum (Verhoeff, 1900), M. lamellifer (Strasser, 1974), M. loebli (Strasser, 1974), M. metsovoni (Strasser, 1976), M. recticauda recticauda (Attems, 1903), and M. taygeti (Strasser, 1976). Thirty-nine species and subspecies are endemic to the Balkan Peninsula, they can be grouped as: (1) species having a wide distribution range; (2) strict endemics of smaller regions; (3) species inhabiting the Peloponnese; and (4) species inhabiting the Greek islands. The Peloponnese and the Rhodopes seem to be remarkably important regions for speciation.
