ABSTRACT
Kellog and Bell (1904) working on the silkworms noticed that if they were fed on insufficient quantities of leaves, their larval life was prolonged, i.e., their pupation or metamorphosis was postponed. Northrop (1917) showed the same state of things in the flies, Drosophila, when reared on food containing little or no yeast. Then, Tangl (1909 (a) and (b)) observed that if the flies were bred on unsuitable food which they did not readily take, they pupated a week later than the normally fed individuals. Thus the researches of all these authors indicated that inadequate feeding, qualitatively or quantitatively, delays metamorphosis. But this general conclusion was contradicted by the works of Krizenecky (1914) and of Szwajsowa (1916) on mealworms (Tenebrio molitor) which pupated much earlier when starved. In order to determine how far the above mentioned general conclusion could be modified, several experiments have been performed on mealworms, of different stages of growth, the results of which are reported in the following pages.
My thanks are also due to the High Commissioner for India, London, who gave me a grant while I was engaged on the present investigation.
