| abstract | A revised classification of the Macronyssidae and Laelapidae (Acarina: Mesostigmata) from bats is presented. The species are placed in 13 macronyssid genera and 2 laelapid genera. Fourteen new species synonyms are given. Five new macronyssid genera are diagnosed: Megistonyssus n. gen. (type—Macronyssus africanus Zumpt & Till, 1958), Parichoronyssus n. gen. (type—Parichoronyssus sclerus n. sp.), Macronyssoides n. gen. (type—Ichoronyssus kochi Fonseca, 1948), Cryptonyssus n. gen. (type—Cryptonyssus desultorius n. sp.), Parasteatonyssus n. gen. (type—Liponyssus nyctinomi Zumpt & Patterson, 1951). The two new type species (P. sclerus and C. desultorius) are described. The family status and relationships of the Macronyssidae are discussed. Hirstionyssus Fonseca, 1948, Echinonyssus Hirst, 1925, Patrinyssus Jameson, 1950, Australolaelaps Womersley, 1956, and Trichosurolaelaps Womersley, 1956, are excluded from the Macronyssidae and provisionally placed in the Myonyssinae of the Laelapidae. An arrangement of family groups for Lllelllpidae and some related families is suggested. |