( xxi ) 



but a conclusion, and that a conclusion may be erroneous. Those who have 

 some experience in systematic work will know that every now and again it 

 happens that the specimens which one author considered to be the same 

 species (or variety) are proved by another to represent several. The reader 

 will find a number of instances illustrating this experience, if he looks over 

 the synonymy in the present work. Therefore, what appeared to be certain 

 may become uncertain again, if there are more than one original specimen. 

 Some authors will, indeed, accept the identification even if it is based on some 

 such mistake, because they consider a name far too nnimportant to justify a 

 strict adherence to principles, if a change of names is involved. However, the 

 majority of classifiers will oppose a name which is incorrectly applied. This 

 spirit of opposition against all mistakes is very healthy. We should deplore its 

 absence ; for we are sure, because we know instances, that he who intentionally 

 overlooks errors in apparently irrelevant matters, will treat in the same spirit 

 also details of fact which appear to him trivial, which may, however, be of the 

 greatest bearing upon general questions, and, therefore, mislead altogether the 

 generaliser who has to depend on the accuracy of the Specialist. 



(b) If it is proved that the original specimens belong to more tlian one 

 species (as do, for instance, the originals of Walker's Macroglossum sitiene, 

 corythus, Nepkele viridescens, etc.), systematists have adopted several methods 

 of narrowing down the conglomerate to one species. These methods are as 

 follows : — 



(<!>') First method of restriction : The name of a composite species is to be 

 restricted to that component which is the first to which the name is afterwards 

 applied bv the same or some other author. Illustration : Macroglossum corythus 



fA, 

 ot 1856 consists of three species -( B, Of these B is the first mentioned as 



lo. 



corythus after 1856; ergo, the name of corythus is restricted to B. — To be 

 certain of the result, it is necessary to know which is the first, and that 

 requires a knowledge of all the books where the name occurs, and, moreover, 

 a knowledge of what is meant therein by the name. These premisses may 

 sometimes easily be got over, but they present more often difficulties which are 

 as intricate as those which the method professes to solve. 



(4-) Second method of restriction : The name is to be restricted to that 

 component of the composite species which remains after the other components 

 have been subsequently separated under new names. Illustration : Macroglossum 



(A, 

 corythus -^ B, As A and B are described as new in 1875, the name corythus 



ic. 



remains for 0. — To arrive at this result, one has to inquire into the descriptions 

 of the new species, in order to find out whether the new names really apply to 

 A and B ; the new species will in many cases again be found to be composite. 

 The method, therefore, creates new difficulties in trying to remove the old ones. 



