BIG-BILLED THICKHEAD. 
rostris , “ the tail black at base, slightly tipped with grey, wing 83, bill 17 ; 
specimen from Barron River, Queensland, has wing 88, bill 13.” 
When Masters described his new species he also gave a description of the 
females of his supposed “ melanura ,” drawing attention to Gould’s suggestion 
that they would be similar to those of gutturalis, glaucura, etc., instead of 
which they were very different. A consideration of the facts suggested that all 
Masters’s specimens must be referable to the same form and I find that North 
has recorded this, stating that Masters had been inclined to agree with him. 
Macgillivray has written : “ This northern form of the Yellow -breasted 
Whistler is found on all the islands along the coast on which there is any scrub, 
but is never seen on the mainland. On Haggerstone Island we noted quite 
a number of these birds, and secured specimens. Dissection indicated that 
they were not then breeding. They probably nest in early spring, as several 
old nests were seen in the scrub. I have, however, a set of eggs in my 
collection taken on Darnley Island on 30th December.” 
McLennan found them fairly plentiful in scrub at Liverpool River Island, 
and in mangrove at Roper River, Northern Territory ; his note was published 
under the heading P. melanura by H. L. White, Emu, Vol. XVI., p. 226, 1917. 
The species is characterised by its longer bill, shorter tail, and female 
coloration. 
The Cape York form will be known as 
Pachycephala robusta robusta Masters. 
Whether this continues down the western side of Cape York Peninsula 
among the mangroves is not known, but Macgillivray records it as on the 
islands only on the eastern side. 
A series from Norman ton, Queensland, were previously classed with 
Pachycephala robusta borroloola Mathews 
from Borroloola, eastern Northern Territory, which I separated from Daly 
River birds on account of the brighter orange -yellow under-surface. I find 
that the Borroloola birds have longer narrower bills and are brighter green 
above, so distinguish the Normanton birds as 
Pachycephala robusta intercedens subsp. nov. 
Erom both, the western Northern Territory males can be distinguished by 
their bigger heavier bills, while the females have the throat darker, more heavily 
flecked, with breast band more pronounced and the yellow under-surface deeper 
in shade. These will be known as 
Pachycephala robusta violetce Mathews. 
The Melville Island race has also a large bill but thinner than the preceding 
with the wing slightly less, while the female has a grey back with the rump only 
green and the yellow under-surface paler. 
