BLACK AND WHITE WREN. 
with their mainland representative ” ; but the plate was lettered with 
binomials suggesting distinct species. This induced Alexander to write a note 
on the matter, suggesting that if it be accepted that the two dark island forms 
had independently evolved from the mainland one, they should either be 
treated as distinct species, or as geographical races of a single species. He 
refers to Whitlock’s views, whereas it was not Whitlock, but Carter who first 
made the suggestion, and the two forms were regarded as subspecific because 
there were slight differences though apparently of little value. 
Alexander pointed out that the coloration of the mainland Blue and White 
Wrens varied in depth, but that the darkest coloured came from the most 
south-westerly portion of the range, and that intermediate forms might be 
found north of Geraldton, admitting however, that typical Blue and White 
Wrens were found on the Edel Land Peninsula, while Whitlock also found 
them on the mainland at Cossack, though suggesting some brown birds were 
referable to the Black and White species. Alexander then stated he would 
regard the island forms as subspecies of the mainland Blue and W T hite Wren, 
a value negatived by the facts he had himself produced. It is probable that 
the two forms have independently evolved, but that is not sufficient at present 
to degrade them to subspecies, and the alternative would be the admission of 
them as distinct species, a value which while phylogenetically correct would 
require more proof than is at present available for its defence. 
Consequently the two forms distinguished cannot be definitely valued, 
and a conservative view would accept two subspecies, though there is so little 
difference to be considered ; the reference to the genus Hallornis is also under 
consideration, but they are undoubtedly different in many ways from 
Malurus. So all I can do is to admit 
Nesomalurus leucopterus leucopterus (Dumont). 
Dirk Hartog Island. 
and 
Nesomalurus leucopterus edouardi (Campbell). 
Barrow Island. 
and leave the matter until a more complete series in all stages of plumage has 
been studied. 
93 
