AbstractThe present paper is the results of the biosystematic studies ofCulex pipienscomplex in China, including hybridization, mathematical analyses of morphological characters and GC analyses of culticular hydrocarbons. On the bases of the results of these studies, in addition to their allopatric distribution, it can be concluded that Cx.pipienscomplex in China consists of four subspecies, includingCx. p ipiens molestusrecently discovered in Beijing.Cx. pipiens quinquefasciatuscan not be considered as a spearate species andCx. pipiens pallensis not an intermediate form as claimed by some western workers.