THE BIRDS OF AUSTRALIA. 
been expressed in the other species in the blue cheeks, blue shoulder patch 
and blue tail. In the present case the blue extends on to the rump and under 
surface, but it is ever antagonistic with the normal green coloration so that it 
has never fully gained superiority. 
To the North-west the xanthochroistic tendency has become dominated 
by a melanistic phase so that we have a black capped species and the yellow 
feathering marked with black. The existence of a distinct form indicates that 
a clashing between the erythristic and xanthochroistic tendencies took place 
and somewhere about New South Wales, probably towards the interior, a 
different form evolved. This form was so strong that it became a dominant 
factor and spread both North and South actually reaching into Tasmania 
again. It is also the most beautiful of all the group. The group is quite 
absent from the interior, and is confined to the coastal region, though it 
ranges well inland. 
A. J. North has contributed a paper to the Records Austr. Mus., Vol. V., 1904, 
p. 265, entitled “ On Heterochrosis in Australian Psittaci ,” which I have already 
quoted. In this paper he treats only of individual cases and a majority refer 
to members of this group. Thus he records xanthochroistic individuals of 
elegans which is normally the most strongly developed erythristic phase. He 
then adds both xanthochroistic and erythristic records of eximius , whose 
plumage shows a balance of these factors. He moreover notes “ I have never 
seen a pure albino of any species of Australian Psittaci .” This is an interesting 
item, as he also added : “ There are numerous instances of abnormally plumaged 
individuals,” meaning where a colour phase was not well defined. 
302 
V 
