PRINCIPLES OF SCIENTIFIC ARRANGEMENT. 139 



are, however, bound by the common affinity of being 

 all beetles. 



It is, nevertheless, often difficult to determine between 

 the relationships of affinity and analogy, for groups even 

 in close contiguity may also possess both. Thus, the 

 normal Ichneumones have their analogues in the Ichneu- 

 mones adsciti, if the comparison be restricted to them- 

 selves, but these revert into the relationship of affinity 

 when a comparison is instituted between them and the 

 adjacent groups on the one side of the Tenthredines, or 

 on the other of the Aculeata, with which, when a re- 

 lationship presents itself, it is merely one of analogy. 

 So, also, within the pentamerous Coleoptera we have 

 a relationship of analogy between the Staphylinidce and 

 the Histeridce, but it becomes one of affinity when it 

 unites them within this section of the class. 



Innumerable other instances might be given readily, 

 but these will suffice to convey a notion of the relative 

 meanings of the terms, ' relation of affinity ' and ' relation 

 of analogy/ which is all here aimed at. 



The problem naturalists have to solve is, " What is 

 the natural system ?" We can clearly see that the sys- 

 tems adopted are not Nature's, that they are essentially 

 imperfect, and that the science, even with all the force 

 of the intelligence that has been applied to it, is far from 

 having attained perfection. It still awaits the master 

 mind that shall cope with its difficulties, determine its 

 intricacies, and, threading the labyrinth, guide his en- 

 thusiastic disciples into the adytum of the temple. 



The subjects here brought under view admit of very 

 considerable development, and of strictly didactic and 

 methodical treatment. It has been my object only to 

 gossip upon them, that I might stimulate curiosity to 



