172 THIRD ANNUAL REPORT OF 



tion — but all these agencies will not produce specific imitation of one 

 species by another, for they only prepare the way for it. It is there- 

 fore quite evident that such imitation can only ^e brought about to 

 use Mr. Bennett's own words, "by the continuous preservation, 

 through countless generations of those individuals which sponta- 

 neously approach most nearly to the ultimate forms;" and Natural 

 Selection is the Preserver. 



I have thus endeavored to frankly consider the objections raised 

 against the theory of Natural Selection, as it applies to the mimicry 

 of our two N. A. butterflies. It would be out of place here, and might 

 justly be considered a work of supererogation on my part to undertake 

 to defend it on more general grounds. It has been so well developed 

 by Darwin, Wallace, Bates', and many other writers, both English, 

 French and German, that it only asks a hearing to be understood and 

 appreciated. The rapid increase of organisms is demonstrable, and 

 the consequent struggle for existence, since, all organisms considered, 

 there are as many deaths as births, is manifest. The result of this 

 struggle is the survival of the fittest, by which organic forms are con- 

 stantly changing to keep in harmony with the changed conditions 

 which it is demonstrable have taken place, and are still taking place, 

 in the inorganic world. And, to use Wallace's language, "as the 

 changes of conditions are permanent changes in the sense of not re- 

 verting back to identical previous conditions, the changes of organic 

 forms must be in the same sense permanent, and thus originate 

 species." 



That its influence and importance has been overrated by some 

 writers is not at all unlikely, for Mr. Darwin himself now believes that 

 he at first attributed too much to its action; and certain it is that it 

 could have had no influence in producing many purely ornamental 

 features of certain animals, that are of no use to the species thus or- 

 namented. No theory was ever yet propounded, however, which has 

 so well stood the test of scientific investigation in all departments of 

 research, or that has such a power of absorbing new facts; and no 

 theory has in such a short time he-en so very generally accepted by 

 the leading scientific minds. 



A two-fold reason has led me to give it prominence in this Report. 

 First, I believe that when well understood it must prove of the utmost 

 importance to the husbandman, by giving him an intelligent concep- 

 tion of the growth and development of animal and plant life about 

 him, and by adding zest and interest to his efforts to produce superior 

 varieties and breeds. Secondly, my studies of insect life led me sev- 

 eral years ago to appreciate the hypothesis, and the more I become 

 acquainted with these tiny beings in the field, the morel become con- 

 vinced of its truth and importance. It is not to be wondered at that 

 the entomologist who treats the different varieties in any group as inde- 

 pendent species, should have implicit faith in the absolute distinctness 

 and immutability of species; but whenever he pays more attention to 



