304 The Mechanism of Evolution in Leptinotaesa 



with a different series of the population involved in the operations. The cli- 

 matic conditions in the location were, on the whole, as indicated in the records, 

 more favorable for the entire population than in the previous season, both 

 being of such a character that one would hardly look for extensive derangements 

 in the array of the population due to the conditions of the environment. There 

 is little doubt that the condition is a perfectly normal one in the population and 

 that the change in its character in successive seasons and generations represents 

 the product of operations that are far too delicate and intricate in their organ- 

 ization and operation to be analyzed by the crude methods that must at present 

 be employed in investigations of this kind in nature. The fact that the climatic 

 records are the product of a meteorological station of itself introduces a huge 

 error, and they are not at this station, nor at any other station that might be 

 chosen, of much service in determining the role of the external condition in the 

 operations that take place in the organisms living there. I have not the least 

 doubt that if it had been possible to have had proper observations at the location, 

 some element in the complex of the environment would have been found that 

 was playing a part in the production of the diversity observed. 



COMPARISON OF THE FINDINGS IN THE COLONIES. 



The conditions presented by the arrays observed in five locations, in different 

 generations and seasons, show phenomena that are of interest and helpful in the 

 further study of the problems of heterogeneity. Most striking is the manner in 

 which this complex character, simple in comparison to the entire organism, shows 

 a ceaseless movement over the field of possible form or pattern conditions in the 

 part. In no two locations, at no two points in time, is one sure of finding the 

 condition in the population the same, even in the array that is present, much 

 less in the proportions and distribution of the population over the area it can 

 occupy. The conditions found are fascinating and suggest vividly the manner 

 in which some distribution enigmas may well have arisen. This production in 

 the population of conditions, first in one direction, then in another, withdrawing 

 from the first but dropping behind, isolated remnants, that conceivably might 

 thenceforward become isolated permanently through diverse natural processes, 

 and so a stem-form with the differing factorial potentialities that this one has 

 might, without further endowment or other natural operations, be productive of 

 a considerable amount of " species formation " as it moved over the substratum 

 on which it lived. Figure 111 shows the conditions of all of the populations in 

 outline, so that the nature of the movements become more striking in their diver- 

 sity in the different locations and generations. 



Another point of interest is the mass action of the population in its response 

 from generation to generation and in the different locations, in the manifesta- 

 tion of the responses in " variation," either determinate or indeterminate, in the 

 sense of Darwin. Both are in this series present together and manifested in the 

 different locations in different ways. Each of the locations chosen showed that 

 the populations respond differently to the complex in which they lived from the 

 response shown in other locations at the same time and generation by the same 

 " species." No question exists that in the Chalcicomula location the population 

 responded definitely, uniformly, in the same manner, to the conditions of the 

 medium, else why so certainly should the introduced strains have gone from 



