INTRODUCTION. 



/\ll{ ret;eiu\'lies in Spli'uKjiilnf, which liiivc liceii ciu-riril mi i-oujoiiitly tor 

 ^"^^ scvfral years, uiul uf whicli we now imblish the resiiils, were uiiderlakeii 

 with liie imriiose nl' giving ii suund basis to the classitictitioii of these insects 

 hy uu extensive simly of their iuor])hology. 



Chissitictitioii is an interpretation of facts. The facts are to a great extent 

 details uf I lie anatomy and morphology of the beings classified. As if, is, 

 therefore, largely eirennistantial evidence wliicii guides the classifier, the first 

 step towards a correct classification is to find out as many facts as [lossibie. 

 In interpreting these facts or characters presented by the individuals— the indi- 

 vidual is the basis of all research — one starts with the assuni[ition tliat what 

 has lieen found to lie true in the necessarily limited number of specimens 

 investigated, liokls gooil also in the vast multitude of individuals not compared. 

 The possibility of an error in this respect can be lessened by the comparison 

 of a large material of individuals. How large it should be, nobody can iiredict. 

 To ascertain the extent of variation of the chief classificatory unit, the sjiecies, 

 the material is never too extensive. 



On the knowledge of the extent of variation of the species of a family 

 depends the stability of the superstructure of genera, tribes, and subfamilies. 

 All ideal classification could be drawn up, if all the species were known which 

 are in existence and which have been. As this premiss cannot be fulfilh^d, we 

 have to be content with the species that are known. And here, again, the 

 foundation of the superstructure will be the safer the more species have been 

 examined. 



^\ e have endea\(iured to comply with these three primary demands on a 

 classifier a> far as it was ])ossible for us : many facts, many individuals, many 

 species. We have not restricted ourselves to a comparison of the pattern, 

 general appearance of the body and wings, and of the neuration, but liave taken 

 into the scope of our research every part of the skeleton of the imagines, and 

 hence have given a broader basis to our conclusions than has ever before been 

 done in this famiiy. .Since the structure of the Hawk Moths has never been 

 studied to any extent — the Sp/dnyu/uc lieing in this respect one of the most 



