WATER RELATIONS IN HIBERNATION. 



233 



early in September and hibernated in the garden alongside of 

 the original stocks, and a further test was made of T 99 in FT 

 in which the first summer generation was crossed as pairs with 

 the normal stock at Chicago, and their FI allowed to hibernate 

 in the garden along with the normal and the stocks from Tucson. 

 The results that were derived in the following spring are shown 



in Table I. 



TABLE I. 



SHOWING THE RESULTS OF THE TESTING OF THE SURVIVAL DURING HIBERNATION 



IN THE WINTER AT CHICAGO. 



* Chicago normal stock. 



These tests were made in wire tubes twelve inches in diameter 

 and forty-eight inches long, placed close together, so that all 

 had as far as one can determine the same conditions during the 

 winter. The findings in the emergence from hibernation in 

 May and June, 1912, show, first, that the condition of non- 

 survival in the T 99 materials concerns the entire population, 

 and that in T ioo, the same change is coming over the stock but 

 did not involve the entire population, 6.5 per cent, surviving. 

 These surviving individuals of T ioo were placed in breeding 

 cages, where most of them died, two females and one male only 

 taking part in reproduction, giving a first summer generation of 

 eleven males and fifteen females, which died without breeding, 

 although given every condition for reproduction. 



The Fi heterozygous population showed complete elimination, 

 or a total dominance of the condition present in the Tucson 

 parent, which was also present in an equal intensity in both 



