STEFAN KOPEC. 



amounted to 5.6 per cent, in series C, to 15.1 per cent, in series 

 D and to 16.8 per cent, in series E; in the females the prolonga- 

 tion was 13.3 per cent, in series C, 20.2 per cent, in series D and 

 28.6 per cent, in series E. 



In series F the caterpillars were fed during two days and de- 

 prived of food during the next two. (Starvation lasting two days 

 every third day + + ++ -). Notwithstanding a differ- 

 ent distribution of the feeding and fasting days, the quantita- 

 tive relation of these days was the same as in series D to which 

 starvation lasting one day every second day was applied (+ 

 + H ); in both experiments the caterpillars experimented 

 upon were of the same age. It nevertheless turned out that the 

 prolongation of life was much greater in caterpillars of series F 

 than in specimens belonging to series D. (Cf. Table II. and III.) 

 In series F it amounted in the average of broods in the males to 

 54.2 per cent, of the average of the life of control caterpillars 

 from their last moult but one, and in the females to 78.0 per 

 cent while in series D the corresponding numbers were 40.5 per 

 cent, in males and 50.3 per cent, in females. The abbreviation 

 of the pupal period calculated similarly was in series F, in males 

 16.1 per cent of the duration of life of control chrysalids and in 

 females 24.6 per cent, while in series D the life of male pupje 

 underwent abbreviation of 5.6 per cent, and of the female 8.7 

 per cent. We see that changes of the duration of the larval and of 

 the pupal stages induced by inanition depend not only on the 

 mutual quantitative relation of the Listing and feeding period, 

 but also on the distribution of tlu-M- periods. The organism 

 responds by more energetic reaction to longer, though less fre- 

 quent, fasting intervals than to more frequent but shorter periods 

 of starvation. 



3. INANITION AND ITS BEARING ON THE PHYSIOLOGY OF INSECT 



METAMORPHOSIS. 



When we try to discuss the foregoing results on the basis of 

 hitherto existing references in the literature, we meet certain 

 discrepancies which, however, may be cleared up by considera- 

 tion of the physiology of animal metamorphosis. 



Kellner ('87) fed caterpillars of the silk-worm during their 

 whole life- on insufficient quantities of leaves, and obtained a 



