This paper presents the results of a study that was largely initiated to describe a genus and species of weevil damaging macadamia fruits in plantations in New South Wales and Queensland, Australia. This taxon is described as Kuschelorhynchus macadamiae gen. et sp. n., the genus named in honour of the late Guillermo (Willy) Kuschel (1918–2017). The related genus Menechirus Hartmann is also revised, resulting in the description of three new species, M. howdenae sp. n., M. parryi sp. n. and M. mundus sp. n. The other genera of the small Australian weevil tribe Cryptoplini, Cryptoplus Erichson, Haplonyx Schoenherr, Sigastus Pascoe and Zeopus Pascoe, are diagnosed and their host associations summarised, and a revised diagnosis of the tribe Cryptoplini is presented, together with a key to its six genera. The extraordinary aedeagus of Cryptoplini, featuring a tectal plate as is characteristic of more primitive weevils, is discussed and illustrated.