SOME ASPECTS OF ANIMAL COLOURA- 

 I TION FROM THE POINT OF VIEW OF 

 COLOUR VISION 



By J. C. MOTTRAM, M.B. Lond., 



The Middlesex Hospital, London 



AND 



F. W. EDRIDGE GREEN, M.D., F.R.C.S., 



Ophthalmic Surgeon, National Service Medical Boards, South London Area 



PART II. 1 



The Consideration of Blue 



With the exception of green, blue is the colour least often 

 found on these insects' wings {vide diagram No. i). Blue and 

 violet are here dealt with together, because the vast majority 

 of the blue tend towards violet rather than green, and because 

 violet was found to have a distribution exactly similar to that 

 of blue. Referring to diagram No. 2, it can be seen that blue 

 differs from all the other colours in that it is much less often 

 found in small than in large or moderate areas. In the five 

 groups considered separately the distribution is : large areas, 

 fifteen times ; moderate areas, seventeen times ; small areas, 

 twenty-three times ; giving a proportion more in favour of 

 the small areas than is the case in diagrams Nos. 1 and 2 : 

 this difference is due to the inclusion in diagrams Nos. 1 and 2 

 of the Lycaenidae, where large areas of blue greatly predominate. 

 The following table (No. 3) gives the arrangements of pattern 

 which are associated with the fifteen instances of large blue 

 areas. It is seen that in every case a very conspicuous type 

 of pattern is found, namely, a central blue area outlined by a 

 band of black or deep-toned brown. In the Lycaenidae this type 

 of pattern is also very common. 



1 For Part I. see July number, 1918, Vol. XIII., No. 49 (Diagrams 1 to 7). 

 17 253 



