THE ADDER. 119 



any one can readily tell an old adder from a young one 

 by the size and build. But assuming that the speci- 

 men to be examined is undoubtedly a young one, how 

 does this affect the colouring ? An examination of a 

 few young adders will at once show that the younger 

 the specimens the more well-defined are the colours. 

 By that is meant that black and yellow, green and 

 brown, are seen more distinctly as separate colours. 

 Of course the specimen must not be too young to 

 show this — not just after birth that is, for at that 

 time the full pigmentation has not taken place. But 

 observe the young after the first spring sloughing is 

 completed, and what has just been stated will be 

 seen. In the same way suppose that the specimen 

 under consideration is an old one. In this case, 

 too, it is not difficult to trace the effect of age. 

 It is observed that the older the adders the less 

 defined are the colours, and the more blending is there 

 of shades. Further than this, the markings are seen to 

 be less distinct. In an old female there is a tendency 

 to a general greenish -brown colour all over the body, 

 and in very old adders the zigzag line and the other 

 marks are sometimes almost obliterated. Photographs 

 do not give much idea of tint, but they do give some 

 indication of the sharpness or otherwise of colours. 

 Thus in the two illustrations here shown — one a young 

 male, the other an old female — the contrast of bright 

 colours and dull shade is quite distinctly seen. Both 

 adders were taken in the Monnow Valley. Any one 



