In the scope of a worldwide revision of the genus Myzocallis, a key of the following subgenera is presented: Agrioaphis Walker (type: Aphis myricae Kaltenbach), Californicallis subg.nov. (type: Myzocallis agrifolicola Richards), Castaneomyzocallis Quednau and Remaudière (type: Aphis castaneae Fitch), Globulicaudaphis Hille Ris Lambers (type: G. pakistanica H.R.L.), Lineomyzocallis Richards (type: Aphis bella Walsh), Myzocallis s.str. (type: Aphis coryli Goeze), Neodryomyzus subg.nov. (type: Myzocallis polychaetus David), Neomyzocallis Richards (type: Callipterus punctatus Monell), Paramyzocallis subg.nov. (type: Myzocallis tenochca Remaudière and Quednau), and Pasekia Aizenberg (type: Hoplocallis komareki Pasek). Four new species of Myzocallis living on various species of Quercus in southern Europe, Turkey, Iran, and Pakistan are described: M. (Neodryomyzus) naumanni sp.nov., M. (Pasekia) mediterraneus sp.nov., M. (P.) persicus sp.nov., and M. (P.) tauricus sp.nov., and a new subspecies, M. (Agrioaphis) castanicola leclanti ssp.nov., host-specific to Castanea in southern Europe. Keys are given for the species belonging to the palaearctic subgenera of Myzocallis.