xx iv Preface to the English Edition. 



more especially, of the older writers, and principally 

 in that of the excellent observer Rosel von 

 Rosenhof, the Nuremberg naturalist and miniature 

 painter. In no single case, however, do the 

 available materials suffice when we have to draw 

 conclusions respecting the phyletic development. 

 We distinctly see here how doubtful is the value 

 of those observations which are made, so to 

 speak, at random, i. e. without some definite 

 object in view. Many of these observations may 

 be both good and correct, but they are frequently 

 wanting precisely in that which would make them 

 available for scientific purposes. Thus every- 

 thing had to be established de novo } and for this 

 reason the investigations were extended over a 

 considerable number of years, and had to be 

 restricted to a small and as sharply defined a 

 group as possible a group which was easily 

 surveyed, viz. that of the Hawk-moths or 

 Sphinges. 



Since the appearance of the German edition of 

 this work many new observations respecting the 

 markings of caterpillars have been published, 

 such, for example, as those of W. H. Edwards 

 and Fritz Mliller. I have, however, made but 

 little use of them here, as I had no intention of 

 giving anything like a complete ontogeny of the 

 markings in all caterpillars : larval markings were 

 with me but means to an end, and I wished 

 only to bring together such a number of facts as 



