RESEMBLANCES AMONG ANIMALS. 83 
it inhabited ; and the results of his observations are 
embodied in a paper published in the Linnean Trans- 
actions, in which he first explained the phenomena of 
“mimicry” “us the result of natural selection, and 
showed its identity in cause and purpose with protec- 
tive resemblance to vegetable or inorganic forms. 
The imitation of the Heliconide by the Leptalides 
is carried out to a wonderful degree in form as well as 
in colouring. The wings have become elongated to the 
same extent, and the antennze and abdomen have both 
become lengthened, to eorrespond with the unusual 
condition in which they exist in the former family. 
In colouration there are several types in the different 
genera of Heliconide. The genus Mechanitis is gene- 
rally of a rich semi-transparent brown, banded with 
black and yellow ; Methona is of large size, the wings 
transparent like horn, and with black transverse bands ; 
while the delicate Ithomias are all more or less trans- 
parent, with black veins and borders, and often with 
marginal and transverse bands of orange red. These 
different forms are all copied by the various species 
of Leptalis, every band and spot and tint of colour, 
and the various degrees of transparency, being exactly 
reproduced. As if to derive all the benefit possible 
from this protective mimicry, the habits have become 
so modified that the Leptalides generally frequent the 
very same spots as their models, and have the same 
mode of flight; and as they are always very scarce » 
~ (Mr. Bates estimating their numbers at about one to a 
thousand of the group they resemble), there is hardly a 
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