INSECT ACTORS in 



variety that, but for its remarkable resemblance 

 to the unpalatable or dangerous species it 

 copies, would readily fall a prey to insect 

 feeders. It is this form of protective resem- 

 blance that constitutes true mimicry, and Wallace 

 has defined the following general condition as 

 being characteristic of this class of protected 

 insects : 



" i. That the imitative species occur in the 

 same area and occupy the very same stations as 

 the imitated. 



" 2. That the imitators are always the more 

 defenceless. 



" 3. That the imitators are always less 

 numerous in individuals. 



"4. That the imitators differ from the bulk of 

 their allies. 



"5. That the imitation, however minute, is 

 external and visible only, never extending to 

 internal characters or to such as do not effect 

 the external appearance." 



Bates, in his travels on the Amazon in 1847, 

 was the first to observe and comment upon the 

 wonderful similarity that exists between certain 

 Butterflies belonging to quite distinct families, 

 and the reason of the resemblance. He noted 

 no less than fifteen species of the Pieridce, a family 

 of Butterflies that have a wide distribution, and 

 to which our cabbage white belongs, that closely 

 imitate different species of the conspicuous and 

 inedible Heliconidae. 



Several species of the genus Papilio (Swallow- 

 tailed Butterflies) mimic the Danaidae of tropical 

 Asia; a brilliant group of Butterflies, some species 



