200 



THE LOWER AMAZONS 



species. I believe these imitations are of the same nature 

 as those in which an insect or Hzard is coloured and marked 

 so as to resemble the soil, leaf, or bark on which it lives ; 

 the resemblance serving to conceal the creatures from the 

 prying eyes of their enemies ; or, if they are predaceous 

 species, serving them as a disguise to enable them to 

 approach their prey. When an insect, instead of a dead 

 or inorganic substance, mimicks another species of its 

 own order, and does not prey, or is not parasitic, may it 

 not be inferred that the mimicker is subject to a perse- 

 cution by insectivorous animals from which its model is 

 free ? Many species of insects have a most deceptive 

 resemblance to living or dead leaves ; it is generally 

 admitted, that this serves to protect them from the on- 

 slaughts of insect-feeding animals who would devour the 

 insect, but refuse the leaf. The same might be said of 

 a species mimicking another of the same order ; one may 

 be as repugnant to the tastes of insect persecutors, as a 

 leaf or a piece of bark would be, and its imitator not 

 enjoying this advantage would escape by being deceptively 

 assimilated to it in external appearances. In the present 

 instance, it is not very clear what property the Callithea 

 possesses to render it less liable to persecution than the 

 Agrias, except it be that it has a strong odour somewhat 

 resembling Vanilla, which the Agrias is destitute of. This 

 odour becomes very powerful when the insect is roughly 

 handled or pinched, and if it serves as a protection to 

 the Callithea, it would explain why the Agrias is assi- 

 milated to it in colours. The resemblance, as before 

 remarked, applies chiefly to the upper side ; in other 

 species ^ it is equally close on both surfaces of the wings. 

 Some birds, and the great ^Eschnae dragon-flies, take their 

 insect prey whilst on the wing, when the upper surface 

 of the wings is the side most conspicuous. 



In the broad alleys of the forest where these beautiful 

 insects are found, several species of Morpho were common. 

 One of these is a sister form to the Morpho Hecuba, which 

 I have mentioned as occurring at Obydos. The Villa 

 Nova kind differs from Hecuba sufficiently to be con- 

 sidered a distinct species, and has been described under 

 the name of M. Cisseis ; but it is clearly only a local 

 variety of it, the range of the two being limited by the 



^ Agrias Hewitsonius and Callithea Markii. 



