YOL. XL VIII, NO. 568 >/ 



APRIL, 1914 



THE 



AMERICAN 

 NATURALIST 



A MONTHLY JOURNAL 

 Devoted to the Advancement of the Biological Science! with 



Special Reference to the Factors of Evolution 



CONTENTS 



Page 



I. The Origin of X Capsella Bursa-pastoris arachnoidea. Dr. Henri Hrs - 193 

 H. Biology of the Thysanoptera. II. Dr. A. Franklin Shtjxl - - 236 



and Mammals. Joseph Gbinneix. Yellow Varieties of Rats. Professor 



THE SCIENCE PRESS 

 LANCASTER, PA. GARRISON, N. Y. 



NEW YORK : SUB-STATION 84 



