Taylor's power law and Iwao's patchiness regression were used to analyze spatial distributions of broad mite, Polyphagotarsonemus latus (Banks), and citrus rust mite, Phyllocoptruta oleivora (Ashmead), on lime trees during winter, spring, summer, and fall between 1985 and 1987. Taylor's power law generally provided a better description of variance-mean relationships for both species than did Iwao's patchiness regression. Both species exhibited aggregated patterns of spatial distribution, but patterns of distribution differed among species. Sample size requirements for fixed levels of precision were determined by using estimated variance-mean relationships obtained from Taylor's power law regressions.