HIBERNATION IN THE POTATO BEETLE. 



non-solanaceous foods like beets, carrots, squash and cu- 

 cumbers. 

 Group 4. Non-solanaceous foods exclusively. 



Number 0} Days Feeding Before 1 Hibernation. 



The number of days feeding on different food plants before 

 hibernation took place is shown in Tables I.-IV., and in Fig. 2. 

 Group i, fed on foliage required an average of 16 days, whereas 

 group 2, fed on tubers and fruit required an average of 13 days. 

 Evidently, to accumulate sufficient nutrients necessitated a more 

 extensive feeding on foliage than on tuber or fruit. The experi- 

 ment with group 3, fed on potato foliage for six days followed by 

 a period of feeding on sliced non-solanaceous foods, resulted in, 

 first, an increase in the number of feeding days essential for 

 nutrient storage to an average of 23.6 days; second, a mortality 

 of 23 per cent.; third, unsuccessful hibernation of 32 per cent, 

 (which died during the process). 



TABLE I. 



NUMBER OF DAYS FOR BEETLES FED ON FOLIAGE TO ENTER HIBERNATION. 



Cages Receiving No Water. 



The general effect with group 4, fed on sliced non-solanaceous 

 foods exclusively and those members of group I, which were fed 

 on pepper plants or its fruit, was one of starvation. Some died 

 after 7 days; others lived for 41 days but were unable to hiber- 



1 Potato beetles hibernating in July or November exhibit the same physiological 

 reactions. 



