WATER RELATIONS IN HIBERNATION. 



235 



Chicago. In the F 2 , however, in both crosses survivals occur, 

 and out of 2,137 hibernated, 443 emerged in the spring of 1913. 

 Two random matings were made from these, of twenty males 

 and twenty females, and large populations grown for the second 

 summer generation and hibernated under the usual conditions, 

 gave in the spring of 1914 the following results: 



These in all ways \vere not to be distinguished from the 

 normal stocks, and allowing for the normal elimination incident 

 to hibernation under the conditions provided, which averages 

 in my garden about twenty per cent., the experiences of the 

 experiment suggest that we have in the F 2 popuulation of 1912 



Observed 

 Expected 



Completely Eliminated, 

 i DD. + 2 Dr. 



1,694 

 1,602.75. . . . 



Surviving, 

 i rr. 



443 

 .534.25 



normal monohybrid. 



In that the normal elimination in hibernation of the Chicago 

 stock runs about twenty per cent., the eliminated individuals 

 in this test of F 2 are surely the combined DD and Dr portions 

 of the population, plus the non-distinguishable dead individuals 

 of the (rr) portion of the array. 



This method of experimentation and testing has been con- 

 tinued in each year to the date of writing, the results of which 

 show that the condition of non-capacity to survive the winter 

 at Chicago is a gradually increasing product of the populations 

 at Tucson, and that the behavior in crossing of the Tucson 

 characteristic is uniformly that of a Mendelian dominant, the 

 normal Chicago condition appearing in F 2 in numbers that are 

 as close to expectation as could be expected. 



Since the discovery of this condition in T 99, all of the intro- 

 ductions of L. decem-lineata have been tested in the hibernating 

 generation with respect to their capacity to survive the winter 

 conditions of the habitat from which the stock came. The 

 results of these tests are presented in Tables III., IV., V. and VI. 



