RELATIONSHIP OF SPECIES. 247 



L. melanoilwrax were born in the same line as sports. . . . The 

 line of rubicunda, which was raised directly, both male and 

 female sports of this kind being obtained, was found to be 

 1 almost completely sterile ' with the parent species, but quite 

 fertile with specimens of rubicunda found at Toluca in natural 

 circumstances." 



The noteworthy point in this matter would appear to be the 

 "almost complete sterility" of the sport rubicunda with the 

 parent species. It would seem at one jump to have arrived at 

 the"D" stage without any of those intermediate graduating 

 stages, as I have suggested in the Theory of Hybrids. This 

 would appear to give it the appearance of a very extreme 

 mutant, all other mutants that I know of being fertile in the 

 first "A" stage with the parent type. As classed in the "D" 

 stage they become associated with types as divergent as the 

 Horse and Ass, that is, of course, as regards their germ plasm 

 interaction, which, as I have tried to show, by no means is to be 

 gauged by the outward appearance, so far as form is concerned. 

 This would appear to discountenance (as stated before in this 

 paper) if not the theory of hybrids, at any rate the suggestion 

 I have put forward that mutations were confined to the somatic 

 or visible evolution, but that the germinal mutation was more 

 gradual, or rather, the effect on the germ plasm was not marked 

 as regards sterility till a much later stage, viz. after two or 

 three mutations, which gives the appearance of a more graduating 

 change in the same. As, however, all these evolutionary matters 

 of varieties, species, and genera, of variants and mutants, appear 

 to be mostly those of degree, it is not incomprehensible to 

 expect more sudden changes at some times than at others, and 

 it would not appear to be any reason that, because some muta- 

 tions, as far as they are germinal, are sudden, supposition of the 

 general tendency of gradual evolution of germ plasm is unsound, 

 or any theories based on this of no worth whatsoever. 



As far as my opinion is of value, this example of the Beetle 

 L. rubicunda appears one of the most interesting facts that have 

 been recorded of any mutants, and equalled only by the curious 

 diverse results of those reciprocal hybridizing experiments 

 mentioned by Darwin. Dr. Lloyd makes no special comment 

 on this in his book (' The Growth of Groups '), although his other 



