CRACTICIDiE. 
not yet reached the black and white stage but have stopped at a black and 
grey one, and the immature is still commonly seen in its speckled grey coloration, 
no black having yet appeared. Gymnorhina shows the same black and white 
as Cracticus, and a more recent stage still is seen in a white-backed species, 
this being entirely opposite to the wholly black Cracticoid development. 
Gymnorhina still shows in its plumage changes the stages it has passed through 
in the evolution of the white-backed form, a series which has provided study 
for local Australian ornithologists with good results. In Strepera we see 
almost a wholly dark coloration, relieved by a little white and the acquisition 
of increased size also. In Neostrepera a wholly grey plumage tending to black 
is still preserved, suggesting the retention of an earlier state of plumage. 
The geographical distribution of these groups agrees very exactly with 
these stages : thus N eostrepera, which seems the most specialised development 
from the ancestral form in One direction lives in Southern Australia, ranging 
from South Queensland to Western Australia with a Tasmanian well defined 
representative. Strepera shows a more restricted distribution, not extending 
to West Australia, but reaching Kangaroo Island, South Australia, and having 
a very distinct representative in Tasmania. These I suggest to be the earliest 
colonists from the North of a pre-Cracticoid ancestor which was developing 
in the North into the black and white pr e-Cracticus-Gymnorhma style. The 
newer development then ranged southwards and developed into the Gymnorhina 
group, which is restricted to Australia, but seems to have extended its range 
to the North comparatively recently. It has a Tasmanian form which shows, 
a very peculiar state in that it is smaller than the Mainland one and, moreover;, 
shows the latest coloration. In this connection we must note the Bulestes 
series, the typical Australian “ Cracticoid,” which also ranges into Tasmania 
but also shows a decrease in size in that island and the latest colour-scheme 
when fully adult, but it seems to be slow in achieving this coloration. Then 
the restricted black and white Cracticus now ranges through Australia in a 
distinct species but does not appear in Tasmania ; and to show these stages 
almost completely, the real black and white Cracticus of extra-limital range 
just crosses the Torres Straits and occurs in the extreme northern limit of 
Australia. At the same time the wholly black Cracticoid bird, Melloria , 
which is typically extra-limital appears in northern Australia in Arnhem Land 
and North Queensland. Thus four stages of invasion are suggested : the 
earliest developing in the south into N eostrepera and Strepera ; the next develop- 
ing into Gymnorhina, perhaps accompanied by Bulestes ; then the true 
Cracticus invasion which evolved C. nigrogularis, and then the most recent 
one when Melloria settled in the north. The case of Bulestes (?) mentalis. 
Salvadori is complex and may indicate a more recent invasion still. 
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