PREFACE vii 



Vertebrate Zoology, University of California, U.S.A. 

 I am indebted to the Director of Agriculture, Iraq, 

 for the data on which Fig. 8 is based : I am also 

 extremely grateful to Miss A. M. Gayton and Mr. 

 Engel Terzi for the line drawings. My friends 

 Mr. C. B. Williams and Mr. W. E. Evans gave 

 me invaluable assistance in the preparation of 

 Chapter I (" The Desert Climate ") and Chapter III 

 (" The Floral Environment "). To my wife, my 

 sister, and my mother my best thanks are due for 

 help in preparing the book for the press. 



P. A. BUXTON. 



Jerusalem. 



June, 1923. 



