336 Mr. P. R. Lowe on Coloration as a Factor in 



that a good many species which I should have thought 

 worthy of geueric distinction, from the point of view of 

 colour-pattern, were not so considered in the ' Catologue of 

 Birds/ but were included with other genera with a perfectly 

 different colour-pattern. Well ! to make a long story short, 

 if Gates had not made new genera for these distinctively 

 coloured species, someone else had. 



Mr. Grant tells me that this group of birds used to be 

 considered the dumping-ground for all doubtful forms whose 

 classification presented difficulties — a sort of waste-paper 

 basket for puzzled or beaten ornithologists. He has kindly 

 allowed me to bring up a few examples^ from this very 

 interesting rubbish-heap, and from them I should be happy 

 to demonstrate to anyone later on the efficacy of colour- 

 pattern as a factor in generic differentiation. Time is too 

 short now to give more examples, but there is a point which 

 I should like to make here. It is this — that as a general 

 rule there is nothing like so much intergrading between 

 colour-patterns characterising genera as there is between 

 such structural generic characters as the form and shape of 

 the bill, the tail, or the wing. And this is just what Ave 

 might expect ; for naturally a highly specialised organ like 

 the bill is constantly subject to minute structural changes in 

 accordance with the functional uses to which it is put, and in 

 correspondence with the type of insect-prey or other food 

 which its owner is accustomed to capture or to feed upon. 



Species are founded on colour, and one of the things 

 which apparently we must not have is intergrading of the 

 colour-factors characterising them. In genera, intergra- 

 dations in, let us say, the form of the bill are apparently 

 admissible. I give you as examples the variable form of 

 the bill in the genus Tringa (the Redshank association), in 

 the genus Erolia, or in the genus Geosinza from the 

 Galapagos Islands, as now comprehended by Mr. Rothschild 

 and Dr. Hartert. 



* Examples of the following genera illustrating the subject were 

 exhibited: — Minla, Schwniparus, Pseudominla (Psittipca'us) , Lioparus, 

 Yuhina, Ixulits, Alcippe. 



