18U 



THE AMERICAN NATURALIST [Vol. LVI 



TABLE V 

 Matings. Both Sexes Together 



The purpose of this second tfsi \va>. of course, to see to 

 what extent duration of life was holding- constant in the 

 line. During the period between the first and second test 

 the stocks of the several lines had been subjected to vary- 

 ing environmental influences, in particular in relation to 

 temperature, the stock bottles having been kept at room 

 temperature, which varied rather extensively. Did the 

 lines after 7 months have the same characteristic life 

 curves that they exhibited on the first test? Allowing 12 



