1 8 STEFAN KOPEC. 



delayed are much older organisms than the control moths. As 

 the imago of Lymantria d is par L. never takes any food, the quan- 

 tity of provisions stored in its body decides the duration of this 

 life-period. From histological research it follows that the amount 

 of this provision which may be noticed in the imago (the so- 

 called adipose body) is in the starved specimens, in relation to 

 their decreased body, not at all smaller than in the controls. 

 This is due to the fact that the starved caterpillars do not form 

 normally sized chrysalids, which contain smaller quantities of 

 the mentioned body, but they are transformed into smaller, 

 even dwarfed specimens. By this circumstance it might be 

 explained why both categories of moths live in general equally 

 long. But in the case of the "starved" moths derived from cat- 

 erpillars the life of which has undergone a very remarkable pro- 

 longation it is obvious that the hunger metabolism during devel- 

 opment caused retardation of natural death of the organism. 

 This I consider to point clearly to the conception of death as a 

 function of the character of general metabolism. According to 

 Ruzicka's researches ('17), the newts, when totally deprived of 

 food, undergo moults more rapidly than control specimens. In 

 connection with my experiments it would be very interesting 

 to ascertain whether the duration of life of such newts undergoes 

 changes. 



More detailed considerations on the cause of especially favor- 

 able influence of intermittent starvation on duration of life of 

 animals are to be found in my former papers (Kopec, '22 a and b.} 



% 



5. SUMMARY. 



1. Intermittent starvation of young caterpillars of Lymantria 

 dispar L. causes considerable prolongation of the larval life as 

 well as a certain abbreviation of the pupal period but has no 

 influence on the duration of life of the imago. These changes 

 increase in proportion as more intense starvation is applied. 

 Larger effects are elicited by longer and less frequent than by 

 more frequent, but shorter, feeding intervals. 



2. The differences of results obtained by various authors in 

 regard to the influence of starvation on metamorphosis depend 

 on differences of age of the animals experimented upon. Tin- 

 caterpillars subjected to inanition approximately from the seventh 



