MIMKTU ANALOGY. 4'J 



(Fig. 3a) ; and Leptalis Theonoe (Fig. 4; as imitating Ithomia 

 Flora (Fig. 4a). These resemblances are sufficiently striking 

 even as shown in our plate, and still more so when observed 

 in preserved specimens in the cabinet ; but it is only when 

 the insects are viewed in their natural state that the palpable 

 intentional imitation is fully seen ; for those features are 

 most developed by nature which produce the most effective 

 deception when the insects are seen alive. 



The object to be gained by this imitation is evident in the 

 majority of cases protection against natural enemies either by 

 concealment or disguise. Those animals that resemble the 

 objects with which they are surrounded, are protected from 

 the observation of others that prey upon them. The ground 

 feeding birds, such as 'the partridge and snipe, the hare 

 amidst dried leaves, the ptarmigan in the snow, the ermine in 

 its winter dress, are all well-known instances of the advantage 

 of the assimilation of colour to that of surrounding objects. 

 In the case of the South American butterflies, the imitation is 

 obviously for the purpose of disguise rather than that of con- 

 cealment. The Heliconidse are a numerous and flourishing 

 group ; and, although slow in flight, are never persecuted by 

 birds or dragon-flies, to which it might be supposed they 

 would be an easy prey ; nor, when at rest on the leaves, are 

 they molested by lizards or predaceous flies which constantly 

 devour butterflies of other families. The Heliconidse seem to 

 owe their safety to their offensive odour, which renders them 

 unpalatable to the enemies of insects ; and even when set out 

 to dry in the cabinet, they are less liable than other specimens 

 to the attacks of vermin. Now it is obvious that the more 

 closely an inodorous butterfly of another species resembles 

 one of the offensive and unpalatable Heliconidae, the less 

 likely will it be to be preyed upon by its natural enemies, 

 which is evidently the cause of the imitations of the genera 

 Ithomia and Methona by the persecuted insects of the genus 

 Leptalis. 



Naturalists differ in opinion as to the origin of these 

 resemblances. " Some naturalists," says Mr. Tegetmeier, 

 " maintain that the resemblances existed from the Creation ; 



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