This figure shows that the distribution of the area-to-total area ratio of the black area of P. minor (Note: The data in the graph were measured from 42 samples. In the figure, miscellaneous colors, i.e., individuals with black proportions between 30% and 90%, accounted for the majority, while light-colored individuals, i.e., individuals with black proportions no higher than 20%, and black individuals, i.e., individuals with black proportions higher than 90%, were very few and only one in our sampling respectively.).