BUTTERFLIES AND ANTS. 183 



" whites " (Picrid&), which, as we all know in the case of 

 our common cabbage-butterfly, are eagerly sought by 

 birds ; and the difference of the mimicking species from 

 an ordinary " white " bj the assumption of the bright 

 colours of the Danaids is so great that nobody but an 

 entomologist would imagine for a moment that it even 

 belonged to the same family. It is, moreover, curious that 

 there is one instance where two species of Heliconids 

 inhabiting adjacent regions are respectively mimicked by 

 two varieties of one and the same species of "white." 



Stranger even than this is, however, the case of certain 

 South African swallow- tailed butterflies. In this group, 

 as a rule, both sexes are alike, and furnished with the 

 characteristic " tails " ; but in one South African species 

 the females entirely lose these appendages, and alter their 

 coloration and the form of their wings so as to mimick not 

 only one, but actually three distinct species of Danaids. 

 Here, then, we have an instance in which a single species 

 of butterfly exists under four totally distinct forms ; viz., 

 the typical swallow-tailed male, and the three varieties 

 of tailless females respectively mimicking the three Danaids. 

 No one would have the faintest idea that the three females 

 belonged to the same family, let alone to the same genus 

 and species, as the male ; while the three varieties of the 

 female would be assigned without hesitation to as many 

 distinct species. That female butterflies are more often 

 protected by mimicry than the males is a fact which may 

 probably be explained by their extreme importance to the 

 race, and also from the circumstance that when heavily 

 laden with eggs they are more likely to fall a prey to birds 

 than are the lighter males. 



A great deal more might be said on the subject of 

 mimicry in butterflies, but we must pass on to our last 

 instance of this feature, which is, perhaps, the most 

 peculiar of all. In this case the mimicked insect belongs 

 to that peculiar group of ants which have the curious 

 habit of carrying in their mouth a leaf which extends 

 backwards over their bodies, and apparently acts as a kind 

 of shade. Now, in British Guiana, there is an insect 

 allied to the cicadas and other bugs, in which the leaf 



