Different biological features of  Icerya seychellarum was studied under four different degrees of constant temperature on mango seedlings, Mangifera indica. Rate of development was 8.0, 2.3 and  1.9 days at 15^oC   for egg, nymphal and adult stages, respectively, while it was 23.8 , 40 and 3.9 days for the same stages, at 33^oC. Hypothetical threshold (zero) of development was 9.2, 10.4 and 12.4^oC for egg, nymphal and adult stages, respectively. Mean thermal units was 85.5, 429.3 and 384.3 degree/ days for egg, nymphal and adult stages, respectively.