Thus for experiments on the artificial rearing of true leaf feeding insects, such as Agrotis and Prodenia, on a totally synthetic media were not so numerous as those of insects boring into leaves and stems. In the present experiments two consecutive generations of the tobacco-cutworm, Prodenia litura FABRICIUS, have been reared succesfully on the totally synthetic media which are composed of casein, glucose, cellulose, cholesterol, choline chloride, ascorbic acid, yeast extract, peanut-oil, Wesson's salts mixture, sodium carboxy methyl cellulose, sorbic acid, sodium propionate, agar and water. Generally speaking, the life historical characters of insects obtained from these rearing experiments are never inferior or rather superior to those of the control reared on the sweet-potato leaves. Consequently, the writers believe that it is essential for obtaining normal adults and their hatchable eggs to add sufficient amounts of the cellulose and either the peanut-oil or vitamin E to the basic synthetic media. The wings of the emerged adults, however, showed more freqently abnormality in size and shape and eggs laid by these individuals were somewhat smaller in number, and a certain percentage being not hatchable. Therefore, the fecundity and hatchability of eggs in these experiments considerably decreased as compared with those of the control. We shall be able to raise still more both the percentage of emerged normal adults and the hatchability of their eggs in further experiments
