Family and Generic Differentiation, 335 



ancestral type of colour-picture, which is either generally fixed 

 in the female or in the immature. From these general 

 considerations, 1 now come to the more practical side of 

 the question of colour-pattern as a factor in generic differ- 

 entiation, and one of the points in this connection is : — 



f6) The correlation of colour-pattern with other generic 

 characters. 



This point I shall dispose of very brieflr, as it is so obviously 

 self-evident, and my time is so short that I do not want to 

 waste it in proving something which anyone can see by 

 opening a series of drawers in the cabinets of the British 

 Museum. 



I do not say that colour-pattern is invariably so correlated, 

 but, whether colour-pattern is used as a factor in generic 

 differentiation or not, it is as a fact correlated in such an 

 enormous number of instances that one cannot help being 

 impressed. Consciously or subconsciously systematists seem 

 in fact to have been guided by it. 



Let me tell you the following story in illustration of 

 this point. While looking for some good examples of this 

 correlation of colour-pattern with generic groups, Mr. Ogilvie- 

 Grant was kind enough to direct my attention to the 

 Babblers — the Crateropodidse. 



I knew absolutely nothing about this group of birds, so 

 that it is fair to say that I came to their study with no 

 preconceived ideas on the genera. I approached the subject 

 entirely from the point of view of colour-pattern, my only 

 aids being the ' Catalogue of Birds ' and Oates's well-known 

 work. So far as my examination extended, I took as a 

 pattern the type of each genus from the ' Catalogue of 

 Birds/ and with those to guide me made a list of all the 

 species which I considered ought to be included in each 

 respective genus on colour-pattern alone. The result was 

 that, so far as Indian birds were concerned, my genera were, 

 as regards species, practically identical with Oates's. On 

 the other hand, as regards the ' Catalogue of Birds,' I found 

 myself constantly in disagreement. I found, for instance. 



