Hierarchical analysis of variation in the frequency of the Standard chromosome arrangement of Drosophila pseudoobscura in the western United States (data from [1], analysis from [7]). Wright uses his rather peculiar method of accounting for sampling error. I haven't gone back to the original data and used a more modern method of analysis.12
66 populations (demes) studied. Demes are grouped into eight regions. The regions are grouped into four primary subdivisions.