174 



to the judgment of the particular naturalist who has to 

 deal with them. 



But let us glance at the subject through the medium 

 of an example, and endeavour to realize what would be 

 the consequence of that wholesale combination at which 

 we must sooner or latter arrive, if genera are not to be 

 upheld because they slowly merge into each other as we 

 recede from their respective types. The immense de- 

 partment Carabid(B, of the Coleoptera, is eminently a 

 case in point. In the details of their oral organs the 

 whole of that family display (as I have elsewhere* re- 

 marked) so great a similarity inter se, or rather shade 

 off into each other by such imperceptible gradations, 

 that the tendency which various clusters of them possess 

 to assume modifications of form which attain their max- 

 imum only in successive centres of radiation, must often- 

 times be regarded as generic, if we would not shut our 

 eyes altogether to the natural collective masses into 

 which the numerous species (however gradually) are, in 

 the main, so manifestly distributed. It is possible 

 indeed that, as our knowledge advances and new dis- 

 coveries take place, we shall so far unite many of the 

 consecutive nuclei which are now considered pretty 

 clearly defined, that we shall be driven at last either to 

 accept the Liansean genera only, or else the entire host 

 of subsidiary ones (albeit perhaps in a secondary sense) 

 which are, one by one, being expunged. And, siace 

 * Annals of Nat. Hist. (2nd series), xiv., p. 199. 



