THE BIRDS OF AUSTRALIA. 
Previously , Milligan had written in connection with birds of Yandanooka 
district, mid- West Australia, under name Pachycephala falcata : “I am in doubt 
whether I am correct in identifying this species as the above, for the same 
reason that I am in doubt whether it is really separable from P. rufiventris. 
Gould’s grounds of distinction between the adult males of the two species were 
that the ear-coverts, lores, and the region around the eyes of P. falcata were 
grey or ashy-grey instead of black as in rufiventris. Both these distinguishing 
marks are not constant, and are found in both species. I secured two adult 
males at Ebano, one having these parts black, and the other having them grey, 
but in all other respects identical. Then, again, I looked at two adult male 
skins obtained by Dr. House in the far north, in the Kimberley expedition, 
one of which possessed these parts black and the other grey. Comparing 
skins from Perth, Yandanooka, and the Kimberley district, there is not any 
difference in any one form, except that the Kimberley birds are not so flaky 
and loose in the plumage as the southern ones. The difference between the 
female birds from the same localities is that in the northern species the longi- 
tudinal brown streaks of the breast are much more narrow ; but this again, 
is variable, for I have handled a skin obtained at Moore River, about 100 miles 
north of Perth, where these lines in the female were very much more narrow 
than in the birds at Yandanooka, 160 miles farther north.” 
The Red-breasted and Red-throated Thickheads have also been a source 
of confusion, as Gould named two forms from South Australia, P. inornata 
andP. rufogularis, then one from Port Essington, Northern Territory, P. falcata, 
and then one from West Australia, P. gilbertii. The two latter were easily dis- 
criminated, partly through the localities being distant, but the two former 
were unrecognised and referred to the present species, whereas they have both 
proved to belong elsewhere, and their history had better be written in the 
proper place. Previously this species had received several names, Latham, 
allotting to it three from the examination of the Watling drawings, twice 
regarding it as a Turdus , the other as a species of Sylvia. Vieillot described 
it as from Africa as a species of Laniarius, while Vigors and Horsfield added 
a new species of Pachycephala, the best location yet. Quoy and Gaimard 
simultaneously considered it a Shrike, placing it under Lanius. 
All these names had been given to the typical form and Gould’s descrip- 
tion of the Port Essington form as a distinct species was the first step in 
differentiation. A long time afterward Ramsay described the Gulf of 
Carpentaria form under the name P. pallida and these two names were 
confused, as pallid birds from the north-west were called pallida, whereas 
they should have been determined as falcata. The consideration of sub- 
species eliminates this kind of error, and several subspecies are separable. 
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