In most insects, geographic variations in voltinism exhibit latitudinal clines, which have been conventionally regarded as a result of climatic adaptation. In contrast, Ypthima multistriata Bulter (Lepidoptera: Satyridae) shows enigmatic patterns of voltinism, ranging from one generation a year, with adult emergence in June or midsummer; to two generations, with adults emerging in June and September; to several generations with adults emerging intermittently from spring to autumn. Local populations with different voltinism patterns are geographically intermingled, suggesting at best a weak relation between voltinism and climatic factors. Y. multistriata populations are highly localized and the species has suffered recent reductions in density, suggesting that the voltinism differences may be of phylogenetic origin and also leading to the species being classified as endangered. To examine whether the geographic variation in voltinism is phylogenetically constrained, we constructed genealogical trees and a haplotype network of populations of Y. multistriata. The phylogenetic analyses of the mitochondrial cytochrome oxidase I (COI) region revealed that phylogenetically close populations, despite close geographic proximity, often display different voltinism. The haplotype network showed the same trends. Similarly, an analysis of molecular variance revealed that the voltinism types hardly accounted for the variance. Thus, we concluded that geographic variation in voltinism of Y. multistriata is at best only slightly attributable to phylogenetic constraints and instead may be due mainly to adaptation to the unique ecological selective regime of each population.