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antennae is of no more significance than the difference of the colour on the 

 wings in which the red is also disappearing, it being replaced by white, or 

 partly first by black. Therefore the antennae in the old form Catilla are still 

 red, whereas in the more recent forms they turn into black, while between 

 these forms, as De Niceville has correctly seen, there occur transitional forms. 

 On account of the great number of specimens which I have been able to obtain 

 in Java, particularly during the so called migrations of this butterfly, and which 

 I could also study by breeding, the whole natural history of this species has 

 grown so thoroughly familiar to me, that, in this regard, I cannot have any 

 more misgivings. For this reason I add here figures of the principal colour- 

 forms in which it occurs in Java; by way of comparison I also add some 

 from other regions of the Indian archipelago. From this we shall be able to 

 see how the same forms occur in different islands ; with differences between 

 the individual insects according to their being more or less advanced in the 

 process of colour-evolution, and connected with each other by all kinds of 

 transitions. In Java I found nearly all the forms, but it must not be forgotten 

 that from that island a much larger material was at my disposal than from 

 the other islands and from the continent of India. Only the $ specimens, on 

 which the black has increased most strongly do not occur in Java ; in Celebes 

 and Salaiara, where very dark 9 specimens occur, some are, however, also found 

 that have not got darker and that, therefore, resemble those of Java and 

 many other islands, which clearly shows that there cannot be any question of 

 local influences. And neither in size, nor in the shape of the wings, is there 

 any difference between those dark specimens and the others. 



According to the rule of the process, called colour-evolution, this species originally 

 must have been red, which colour subsequently through different shades of red, 

 orange and yellow paled into white, while in the meantime sometimes a strong 

 increase of the black and after this again a decrease of this colour, took place. 

 Everything, however, very unequal in its progress, according to the different 

 regions, the sexes and also individually, nay, even appearing unequally on 

 special parts of the wings. A number of such different forms of colour has 

 even until now been preserved in this species; very important for the study 

 of the process of colour-evolution. Red butterflies— still existing among other 

 Pieridae, (P. Nero F.) that yet descend from the same original form, — do 

 not exist any more in this species, neither are such important relics found of 

 the red colour as f. i. still occur in I. Glaucippe L., even the evolutionary 

 stage in which the red has turned into a strong yellow, still occurs only in a small 

 number of specimens. In these, however, often something of the red has also been 

 preserved, especially on the under-side of the hind-wings, where, as it was 



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