WARNING COLORS, WITH EXAMPLES 



145 



The Swallow-Tail Butterflies and their 

 Curious Larv^ 



OW many times I have seen 

 the beautiful yellow and 

 black tiger swallow-tail 

 butterfly dashing here and 

 I there in his headlong flight 

 ' through the woods! It is not 

 often a near glimpse is had 

 of this active species unless 

 he is taken unawares. It is 

 therefore a pleasure to show 

 this butterfly in the photo- 

 graphic illustration while he 

 is making a momentary visit 

 to his favorite flower. This 

 individual was found during 

 the month of August in a field 

 of red clover, where he was 

 taking his sip of nectar. The 

 female sex of this species has 

 two color forms in the south- 

 ern United States, where, be- 

 sides the present yellow form, 

 another black form also occurs. 

 The black form was thought 

 to be a distinct species by earlier naturalists, but it was later 

 ascertained that both forms could be hatched from eggs of the 

 yellow females, and conversely, the eggs of the black female 

 after development often give rise to yellow females. A most 

 interesting feature of this black form known as glaucus is 

 that it mimics another common black swallow-tail butterfly, 

 philenor. It forms one of a trio of butterflies which have this 

 tendency to mimic the model philenor, as previously mentioned 

 in the chapter on Mimicry, at the beginning of this section. 

 The caterpillar of our tiger butterfly, when full grown, is 



