Preface 



horse, as disclosed in fossils then recently dis- 

 covered in the Far West, maintaining that they 

 afforded unimpeachable proof of organic evolu- 

 tion. His principal lecture is here given. 



In a remarkable held of "natural selection" 

 Bates, Wallace and Poulton have explained the 

 value of "mimicry" as an aid to beasts, birds, 

 insects, as they elude their enemies or lie unsus- 

 pected on the watch for prey. The resem- 

 blances thus worked out through successive 

 generations attest the astonishing plasticity of 

 bodily forms, a plasticity which would be in- 

 credible were not its evidence under our eyes 

 in every quarter of the globe. Insects have 

 high economic importance as agents of destruc- 

 tion: we are learning how to pit one of them 

 against another, so as to leave a clear field to the 

 farmer and the fruit grower. In this depart- 

 ment a leader is Professor Howard, who con- 

 tributes a noteworthy chapter on the successful 

 fight against the pest which threatened with ruin 

 the orange groves of California. 



To the every-day observer the most enticing 

 field of natural history is that in which common 

 flowers and common insects work out their un- 

 ending co-partnery. A blossom by its scent, its 

 beauty of tint, allures a moth or bee and thus, in 

 effect, is able to take flight and find a mate 

 across a county so as to perpetuate its race a 

 hundred miles from home. Our volume closes 

 with a sketch of the singular ties which thus bind 

 together the fortunes of blossom and insect, so 

 vii 



