Malagasy Epilachnini are one of the least studied groups of the herbivorous ladybird beetles. Most of the species were described in the 19th and 20th centuries and their position within the modern classification has never been examined. Here we provide results of detailed study of two species Epilachna hovana Sicard, 1907 and Peralda quadriguttata, Sicard, 1909 which are proposed to be transferred to the genus Merma Weise (comb. nov.). Detailed morphological analysis, photographs of male and female genitalia and a key to species are also provided.