Examination of PRADHAN'S Theory relating to the Relation of Temperature to the Development of Insects.

PRADHAN'S theory relating to the relationship between temperature and the velocity of insect development has been examined using the data published by previous workers. It has been found that the formula proposed by PRADHAN may be applicable to the data obtained with Gnorimoschema operculella and Chilo simplex, of the data examined by the writer. In the case of the other insects, PRADHAN'S formula can not be applied; because in these cases the velocity curves are found to possess a straight line portion in a fairly wide range of the medial temperatures. The examples of such cases are: Lepidoptera Bmbyx mori; Coleoptera Callosobruchus chinensis, Acanthoscelides obtectus; Hymenoptera Eutomostethus juncioorus, Neocatolaccus mamezopha gus; Diptera Chactodacus cucurbitae. Another point of interst is that PRADHAN's formula does not seem to fit the experimental data accurately when temperatures of rearing are beyond the temperature of the maximum rate of development. This seems to be due to the fact that tile velocity curve of insect development is in most cases not symmetrical on the right and left sides, the central point being the temperature of the maximum development. This point, however, seems to be worth further investigation.