CHAP. XX CELEBES 463 



Dichorrhagia, which has a very close ally in the Himalayas, 

 but nothing like it in any intervening country. These 

 facts call to mind the similar case of Formosa, where some 

 of its birds and mammals occurred again,under identical or 

 closely allied forms, in the Himalayas; and in both in- 

 stances they can only be explained by going back to a 

 period when the distribution of these forms was very 

 different from what it is now. 



Peculiarities of Shape and Colour in Celelesiaoi Butter- 

 flies. — Even more remarkable are the peculiarities of shape 

 and colour in a number of Celebesian butterflies of different 

 genera. These are found to vary all in the same manner, 

 indicating some general cause of variation able to act upon 

 totally distinct groups, and produce upon them all a com- 

 mon result. Nearly thirty species of butterflies, belonging 

 to three different families, have a similar modification in 

 the shape of their wings, by which they can be distinguished 

 at a glance from their allies in any other island or country 

 whatever ; and all these are larger than the representative 

 forms inhabiting most of the adjacent islands.^ No such 

 remarkable local modification as this is known to occur in 

 any other part of the globe ; and whatever may have been 

 its cause, that cause must certainly have been long in 

 action, and have been confined to a limited area. We 

 have here, therefore, another argument in favour of the 

 long-continued isolation of Celebes from all the surround- 

 ing islands and continents — a hypothesis which we have 

 seen to afford the best, if not the only, explanation of its 

 peculiar vertebrate fauna. 



Concluding Remarks. — If the view here given of the 

 origin of the remarkable Celebesian fauna is correct, we 

 have in this island a fragment or outlier of the great 

 eastern continent which has preserved to us, perhaps 

 from Miocene times, some remnants of its ancient animal 

 forms. There is no other example on the globe of an 

 island so closely surrounded by other islands on every 

 side, yet preserving such a marked individuality in its 



1 For outline figures of the chief types of these butterflies, see my Malay 

 Archipelago^ Vol. I. p. 441, or p. 216 of the tenth editiou. 



