THE TRIBE OF THE ANGLE-WINGS 163 



others have just been disclosed from the protecting walls 

 of the chrysalis. 



The world-wide distribution of this butterfly is shown 

 in the statement that it occurs throughout Europe, and 

 in North America from Newfoundland to Cuba and 

 Guatemala. It is a safe guess that it is found in practi- 

 cally all localities where nettles grow. 



It is not alone the association between a butterfly cater- 

 pillar and its host plant which has been brought about 

 during the long ages through which one generation has 

 been succeeding another, but there have been also many 

 developments of similar associations between the cater- 

 pillars and their parasitic enemies. The Red Admiral is a 

 good example of such a development. During its long 

 growth as a species it has been exposed to attack by vast 

 numbers of tiny foes which live at the expense of other 

 insects. Several of these foes have found in the bodies 

 of the caterpillars good opportunities for growth, so that 

 now the Red Admiral, as a species, has to reckon with 

 many enemies among these tiny parasites. The inter- 

 action between caterpillar host and uninvited parasitic 

 guest has much to do with the great irregularity in the 

 numbers of the butterflies. It is simply another example 

 of that complicated struggle for existence, by means of 

 which nature keeps ever a fairly even balance of her 

 myriad forces. 



The Painted Beauty 



Vanessa huntera 



One of the most interesting phases of the study of but- 

 terflies is to learn how often they take advantage in their 



