Megalorhina Westwood (type species: Ceratorhina (Megalorhina) harrisii Westwood, 1847) was synonymysed previously with Amaurodes Westwood (type species: Ceratorhina (Amaurodes) passerinii Westwood, 1844), and Amaurodes ranked as a subgenus of Mecynorhina Hope (Holm, 1993). Here, Megalorhina is raised from the synonymy with Amaurodes and treated as a subgenus of Mecynorhina. The type species of Mecynorhina (Megalorhina) is identified and re-described. M. (M.) leptofurcosa (Allard, 1985) is synonymised with M. (M.) harrisii. M. (M.) mukengiana (Kolbe, 1884) is raised from the synonymy with M. (M.) harrisii and recognized as a bona species. M. (M.) harrisii harrisii sensu Allard (nec Westwood) is synonymised with M. (M.) mukengiana. M. (M.) taverniersi (Allard, 1990) is confirmed a bona species. M. (M.) haroldii Thomson, 1880, is raised from the synonymy with M. (M.) harrisii and ranked subspecifically under the latter. M. (M.) procera (Kolbe, 1884) and M. (M.) schaueri (Schürhoff, 1933) are synonymised with M. (M.) haroldii. M. (M.) eximia (Aurivillius, 1886) and M. (M.) peregrina (Kolbe, 1895) are confirmed subspecies of M. (M.) harrisii. M. (M.) dedzaensis, subsp. nov., is described as a subspecies of M. (M.) harrisii. The valid species and subspecies of subgenus Megalorhina are listed below: 1. M. (M.) harrisii (Westwood); 1a s. str. Westwood; 1b ssp. haroldii Thomson; 1c ssp. eximia Aurivillius; 1d ssp. peregrina Kolbe; 1e ssp. dedzaensis subsp. nov.; 2. M. (M.) mukengiana (Kolbe); 3. M. (M.) taverniersi (Allard). The subgeneric classification of genus Mecynorhina is also discussed and five distinct subgenera identified: Mecynorhina Hope s. str.; Chelorhinella subgen. nov.; Mecynorrhinella Marais and Holm; Amaurodes Westwood; and Megalorhina Westwood. The known species, subspecies and colour varieties of subgenus Mecynorhina (Megalorhina) are discussed, re-described and illustrated. The aedeagi are photographed for the first time. A dichotomic key to all valid taxa is provided.