WATER RELATIONS IN HIBERNATION. 



239 



of the tested populations, or a total elimination incident to 

 hibernation of the second summer generation of these animals 

 of about twenty per cent, of the population, about eighty per 

 cent, emerging in the following spring. In nature, however, the 

 elimination is greater, due no doubt to agencies that are elimi- 

 nated under the conditions of these tests, which completely cut 

 off all the losses that might come from burrowing animals that 

 might use them as food, and probably other agencies as well. 



In Table VIII. are given the combined results of the testing 

 of the introduced cultures at Tucson, respecting their ability to 

 survive the hibernating season of their native habitat. 



TABLE VIII. 



SHOWING THE COMBINED RESULTS OF THE TESTING OF THE CULTURES T 99, T 100- 

 T 100 A, T 100 B, T 100 C, FROM THE SECOND TO AND INCLUSIVE OF THE SIX- 

 TEENTH GENERATIONS. IT SHOULD BE NOTED THAT THE PERCENTAGE OF ELIMI- 

 NATION BEFORE HIBERNATION, REMAINS ABOUT AT THE AVERAGE FOR THE 

 SPECIES AS SHOWN IN TABLE BUT THAT THE ELIMINATION DURING HIBERNATION 

 INCREASES, UNTIL ABOUT THE SIXTH GENERATION, WHEN IT BECOMES TOTAL, 

 AND REMAINS so TO THE END OF THE SERIES TO DATE. 



Comparison of the data in Tables VII. and VIII. shows con- 

 clusively: First, that the elimination in the preparation for 



