We report information about the structure of the karyotype of the ant-attendedmealybug Neochavesia caldasiae that maintains an obligate association with antsof the genus Acropyga. Seven pairs of holocentric chromosomes (2 = 14) constituteit, with one pair larger that the other six. This number is discussed according the toinformation available about the Pseudococcidae karyotype evolution, focusing theRhizoecinae.