354 Mr. H. W. Bates's Coniriuutions 



the difTerences vvoulfl generally be considered of a specific charac- 

 ter, and which involve all the individuals in the locality, but 

 which at the same time have all the appearance of geographical 

 varieties, I have thought it best to treat as doubtful species. The 

 perfectly distinct forms are introduced without a mark of doubt; 

 they are distinct from the species, or series of doubtful species 

 which precede them on the list, but are connected with the doubt- 

 ful species which follow them. Even with this arrangement I 

 cannot conceal from myself that the distinctions are still too 

 arbitrary; viewed in nature the forms appear to blend into each 

 other much more than they do in the following arrangement. 

 Nature, as far as species are concerned, wears a false air of sim- 

 plicity in all our lists and monographs. There are in some 

 species individual diflPerences which it is difficult not to consider 

 as important as described varieties ; the varieties too are of many 

 degrees of importance, some of a very partial nature, others em- 

 bracing a large proportion of individuals and occurring only in 

 certain localities, which latter might be considered with almost 

 equal justice as local varieties or sub-species. Local varieties 

 again are sometimes of a slight nature, whilst at others assume 

 forms so well defined tluit it is difficult to exclude them from the 

 category of full species. There is no absolute, well defined dis- 

 tinction between these different grades of relationship, and there-., 

 fore there are in the following list many forms which I consider 

 it merely a matter of individual opinion under what category to 

 treat them ; some varieties might be considered mere individual 

 differences, some local varieties as true or complete species, and so 

 forth. Tills question, I think, is not of so much importance as cer- 

 tain others which might be raised concerning them. I will only add 

 here that I have considered the series of doubtful forms related 

 to P. Vertumnus, sp. 2, to end at sp. 4, beginning those related to 

 P. Proteus with sp. 5. T have separated the two series of forms 

 somewhat arbitrarily, as there is no break in the connecting links ; 

 P. Zeuxis of the one series being extremely near P. Phosphorus of 

 the other. The extreme forms, however, of the two series, viz. 

 P. Panares or Iphidamas and P. Vertumnus, are so dissimilar that 

 I have thought it best at present to separate the two groups of 

 semi-species which they respectively represent. Future dis- 

 coveries will, no doubt, serve to link all these forms still more 

 closely together, and it will then remain a remarkable fact that the 

 local modification of form affects the tendency to return into the 

 normal form, or amalgamate, when varieties thus produced are 

 brought by natural re-distribution into contact ; because P. 



