3 88 



DAVID E. FINK. 



no breeding activities before dormancy set in. The beetles 

 hibernated during July and August and remained in that state 

 until the following season. Other experiments conducted by 

 confining first generation beetles with normal food plants in 

 field cages, produced similar results. During fall and winter 

 these hibernating beetles were frequently removed from the soil 

 in the cages, and sections made of the testes revealed mature 

 sperm in abundance. Dissections of the females yielded im- 

 mature ova. These results are contrary to those obtained by 

 Tower (24), who states, "The first brood on emergence feeds for 

 a few days and then deposits eggs for a second generation. The 

 second generation does not develop the germ cells nor show any 

 reproductive activity until after it has passed through a period 

 of hibernation or aestivation." 



Metabolism During Feeding Experiments. 



During the progress of feeding a veritable storing of food in 

 the form of fat takes place in the adipose tissues of the animal 

 (Fig. 4). It has been pointed out above that a numerical 

 difference in days exists, for nutrient storage when different foods 

 are fed. From metabolism determinations it seems possible to 

 correlate the results procured during the feeding experiments 

 with the oxygen consumption. In Fig. 3, the oxygen intake per 

 gram organism in cubic millimeters per hour is shown. From 

 an examination of this figure it is evident that a reduced oxygen 

 consumption takes place when tuber or fruit material, as com- 

 pared to foliage, is fed. Obviously then the process of converting 

 tuber material required less oxygen. The analysis of food plants, 

 given in Table V., shows the amounts of carbohydrate and fat 



TABLE V. 



SHOWING ANALYSIS OF FOOD PLANTS IN PERCENTAGE. 



