xiv l^ranslators Preface. 



It gives me much pleasure in conclusion to 

 express my thanks to Dr. Weismann, not only for 

 the readily given permission to publish an English 

 translation of his work, but also for much valuable 

 assistance during the execution of the task. The 

 author has been good enough to superintend the 

 drawing of the plates for this edition, and he has 

 also read through the greater part of the manu- 

 script. From Mr. Darwin also I have received 

 much kindly encouragement, and among ento- 

 mologists I am especially indebted to Mr. W. H. 

 Edwards of West Virginia, for his valuable ad- 

 ditions to the first part. To my friends Mr. A. 

 G. Butler, Mr. Roland Trimen, and Mr. F. Moore, 

 I owe acknowledgments for much useful in- 

 formation concerning the caterpillars of exotic 

 Sphingid& } which I have incorporated in the 

 notes and appendices, and Mr. W. S. Simpson 

 has given me occasional advice in the translation 

 of some of the more difficult passages. 



R. M. 



London, November ; 1881. 



