PARTHENOGENETIC PURE LINE OF APHIS AVEKLE FAB. 6 1 



TABLE I. Continued. 



We note that there is a great fluctuation in the fraternal means 

 obtained. During the early selections, disregarding these flue- 

 tuations, the general trend appears to be the augmenting of the 

 fraternal means. But during the latter part of the experiment 

 there is a decided drop in the means, and the last one obtained, 

 3.250, is much below the mean for the whole line. Hence we 

 fail to find in the continuous selection for n generations that any 

 permanent effects were produced. But why the great rise and 

 fall in the fraternal means? This I attribute to the great variation 

 in the size of the individuals obtained, which variations were 

 closely correlated with the variations in the absolute cornicle 

 length. The size variation was undoubtedly influenced by the 

 change in temperatures, as I succeeded in demonstrating later. 

 The results of this demonstration will be given beyond in this 

 paper. Selection, therefore, failed to influence in the least the 

 mean length of the cornicles in the pure line of Aphis avence Fab. 



