40 CONTROLLED NATURAL SELECTION 



it may be induced to strike them rather than 

 more vulnerable parts, which have not eye- 

 spots. Other marks and colourings serve 

 the same purpose ; for instance, the brilliant 

 under- wings of many moths. 



Here are examples of purposely conspicuous 

 characters whose function is to attract enemies. 

 Whenever conspicuous colouring is found on 

 invulnerable parts, the question must be asked, 

 Is this an attracting mark ? There is some 

 evidence that these marks are by no means 

 uncommon. In birds, for instance, the con- 

 spicuous marks and bars on wings and tail 

 may be of this nature. As is often the case in 

 insects, they are concealed when at rest and 

 displayed during flight, and may cause enemies 

 to strike at tail or wing and thus not injure 

 vital parts. 



It is noteworthy that although young as 

 a rule do not present conspicuous colouring, 

 they do usually have these attraction marks. 

 (For examples see Chapter IX.) 



It will be well to review the conclusions 

 which have been arrived at in the last two 

 chapters : 



1. Purposeful conspicuousness of animals 

 is a fact of Nature. 



2. It is produced in animals by means of 



