vi PREFACE. 



evolutionary biologists ; and I have ventured ac- 

 cordingly to work it out here to its furthest 

 legitimate conclusions. 



My acknowledgments are due in the highest 

 degree to Sir John Lubbock's admirable little work 

 on British Wild Flowers in Relation to Insects, 

 and to Mr. Bentham's British Flora. I also owe 

 much to Sir Joseph Hooker's Student's Flora, 

 to Professor Sachs's Botany, and to other books 

 too numerous to mention. Personally, I have to 

 thank my friend Mr. F. T. Richards, Tutor of 

 Trinity College, Oxford, for many valuable sug- 

 gestions and corrections of which I have gladly 

 availed myself. 



G. A. 



