The author intended to express the variation rate of the isophenes which was reported in this magazine.
Let y be the date of phenologicaloc currence, _??_ the latitude, λ the longitude, and h the altitude of a station. The following assumption was made y=a+b(_??_-35°)+c(λ-135°)+dh Using the observed data, the values of constants in the mathematical expressions were computed for the animal phenology above mentioned. The results of computation were given in the table 1. The value of b decreases as month goes on from spring to summer, while, on the contrary, it increases in absolute value from summer to winter. The value of dt/dψ was calculated by the figure 2 and the dt/dψ diagram for temperature was obtained. This shows that the rate of dt/dψ is smaller in higher latitude and in higher temperature than in lower altitude and in lower themperature. This variation of dt/dψ has something common with b in animal phenology in Japan.