32 STEFAN KOPEC. 



duration of the pupal stage in the filial generation must be on the 

 contrary explained in a different manner. It has been shown that 

 the abbreviation of the pupal period and consequently the accel- 

 eration of development of the embryonal discs was brought 

 about even by temporary starvation of very young caterpillars, 

 viz., lasting 20 days after hatching from eggs, i.e., at a time when 

 there are in the larval organism not yet any traces of histolytical 

 processes characteristic of pupation (Kopec, '21 and '23). It 

 may therefore easily be assumed that not only the embryonal 

 discs of the animal subjected to inanition, but also the evolutive 

 factors contained in their sexual cells, which cause the evolution 

 of the embryonal discs in the filial generation, are stimulated to 

 development by starvation and by the decreased checking 

 function of the brain connected therewith. In the caterpillars 

 of this filial generation the brain finds therefore the embryonal 

 discs which are more physiologically advanced and this fact 

 eventually leads to a certain abbreviation of the pupal stage of 

 the progeny of starved females or of starved males. 



On surveying the results of the foregoing inquiry the following 

 summary may be given : 



1. The females of the moth Lymantria dispar L. derived from 

 starved caterpillars mated with control males laid smaller 

 quantities of eggs than control specimens, but the dimensions 

 of the eggs and the weight of the pupa? developing from them did 

 not undergo any essential changes. The capacity of the egg to 

 develop and the mortality of caterpillars as well as of chrysalids 

 are not changed by the starvation applied in these experiments 

 as compared with control material. 



2. The morphological structure of the spermatozoa of males 

 deriving from similarly starved caterpillars is unchanged and 

 they have the normal capacity for stimulating eggs to develop- 

 ment, but the mortality of the resulting caterpillars and chrysalids 

 is distinctly larger than that of the control material. The weight 

 of the pupa? in the progeny of starved males undergoes essential 

 decrease. 



3. Distinctly injurious effects were consequently brought about 

 in the offspring by inanition of the males, in contrast to inanition 

 of the females. The causes of the different behavior of either of 

 the starved parents ought to be referred to metabolism probably 



