Phylogenetic analysis is critical to an evolutionary understanding of any character distribution, including that of sexuality, and yet there has been no concerted effort to apply phylogenetic methods to studying the evolution of sex. This study will examine the phylogenies of two related groups of South American weevils that consist primarily of parthenogenetic species. Morphological evidence indicates that each group includes a speciose clade that is primitively parthenogenetic. The study will rely primarily on mitochondrial DNA sequences for phylogenetic analysis. Flow cytometry and allozyme data will be used to confirm the distribution of parthenogenesis and to provide additional data on relationships among clones. The ages of parthenogenetic clades and their origination and extinction rates will be estimated using DNA sequence data. This study will lay the groundwork for testing theories of sex using parthenogenetic weevils; it aims to serve as a model for a much-needed program of phylogenetic research into the evolutionary biology of sex.