On a General Theory of Adaptattori and Selection. 429 



curve; and this external "character" too, is compound or at 

 least representative of a series of external influences that affect lepi- 

 doptera, for not only will temperature conditions agree with calen- 

 dar time, but food-supply and many other things will follow in a 

 general way the temporal curve. It is clear, I think, that a certain 

 degree of correlation between time of the year and metamorphosis 

 will be adaptive, while a low degree will be unadaptive. Those 

 individuals that mature too early will, even if they find mates, 

 produce eggs and larvae that will find poor food-supply, while 

 those that emerge too late, supposing that they too find similar 

 mates, will produce larvae that will not have time to become full 

 fed before cold weather will kill them and cut off their food-supply. 

 Facts might be cited, showing still further that those that differ 

 most from the average as regards the time of metamorphosis, 

 vary also in unadaptive directions in internal characters, produc- 

 ing few eggs, possessing imperfect wings, and in other ways. 

 It is needless to amplify the disadvantages that a lack of correla- 

 tion with external influences or conditions would entail. 



In brief, then, we find that the principle of correlative basis for 

 selection involves not only the whole constitution of the organism 

 itself, but the whole series of graded external influences as well, 

 be these inorganic or organic, homogeneric or heterogeneric. 



IV. 



A few words are necessary with regard to the relations of the 

 conception presented above. In the first place, it differs from 

 the general theories hitherto brought forward in having a concrete 

 basis in the results of statistical investigations of correlation and 

 variation, and secondly, in that it places the series of external con- 

 ditions on the same plane as the series of internal conditions, 

 in their relation to the final welfare of the organism, regarding 

 them also as varying according to the familiar laws of error. 

 How far it may be justifiable to extend this principle over the 

 external world, remains for future investigation; but it will be 

 possible, as I belive, to utilize statistical methods in such inves- 

 tigations. 



Selection is not regarded as in any way originative but only as 

 judicial, so to speak. As the members of any species present 

 themselves at the bar, "selection" decides the question of survival 



