Table 2 



Biochemical composition of potato leaves 



Table 3 



Prolificness of 100 females 



The beetles were analysed, too, in different periods of their life. 



In table 1 one sees that the length of the day has very essentially influenced 

 the course of the plants vegetation and their yield. 



The results of biochemical analyses of plants are given on table 2. It can be 

 seen clearly that the leaves of plants grown in a diffused light have much lower 

 — contents of dry substance. Other elements rather do not differ from each 

 other and do not explain the different behaviour of the Colorado beetle fed 

 with different food. Any influence of the photoperiod on the length ob the 

 beetles activity manifested itself in a very strong degree. Namely the activity 

 of those bred in a short day was reduced to 7—10 days. During that time they 

 fed intensively and then rapidly went down into the earth and fell into a dia- 

 pause. The activity of beetles bred in a long day was considerably longer, 

 amounting to 40—50 days, many of them altogether did not descend into the 



232 



