488 



from their varied mode of life in different stages of development, 

 and perhaps for other reasons, the species are less likely to be 

 destroyed in the progress of geological changes. 1 Cataclysms and 

 submergences, which would annihilate the higher animals, would 

 only float the temporarily asphyxiated insect, or the tree trunks 

 containing the larva; and pupae to other neighboring lands. How- 

 ever that may be, I have given you some grounds for believing, 

 that many of the species of insects now living existed in the same 

 form before the appearance of any living genera of mammals, and 

 we may suppose that their unchanged descendants will probably 

 survive the present mammalian fauna, includine- our own race. 



I may add, moreover, that some groups, especially in the 

 Rhynchophora, which, as I have said above, I believe to be the 

 earliest introduced of the Coleoptera, exhibit with coinpaet and 

 definite limits, and clearly defined specific characters, so many_ 

 generic modifications, that I am compelled to think that we have 

 in them an example of the long sought unbroken series, extending 

 in this instance from early mesozoic to the present time, and of 

 which very few forms have become extinct. 



I have used the word species so often, that you will doubtless be 

 inclined to ask, what, then, is understood by a species? Alas! I 

 can tell you no more than has been told recently by many others. 

 It is an assemblage of individuals, which differ from each other by 



than those in which they differ from any oth< i >-embla-< ot in- 

 dividuals. Who determines the value of these characters? The 

 experienced student of that department to which tiie objects be- 

 long. Species are, therefore, those groups of individuals* repre- 

 senting organic form- whmh u;i i:i:< o<.\[/.r.i> n> such by those 

 who from natural power and education are best qualified to judge. 



You perceive, therefore, that we are here dealing with an entirely 

 different kind of information from that which we gain from the 

 physical sciences ; everything there depends on accurate observa- 

 tion, with strict logical consequences derived therefrom. Here 

 the basis of our knowledge depends equally on accurate and 

 trained observation, but the logic is not formal but perceptive. 



