THE BIRDS OF AUSTRALIA. 
Smicrornis brevirostris stirlingi Mathews. 
Stirling Ranges, South-west Australia. 
Differs from S. b. occidentalis in having less yellow on the under -surface 
and the back brownish-green. It is also slightly smaller. 
Smicrornis brevirostris viridescens Mathews. 
South Australia. 
Differs from S. b. brevirostris in its darker green coloration above, more 
spotting on the throat, and brighter yellow on the flanks and abdomen. Type 
locality : Tailem Bend, South Australia. 
Smicrornis brevirostris mathewsi S. A. White. 
Central Australia. 
“ Differs from S. brevirostris in being much lighter on the back, and the 
yellow of the breast and abdomen being much brighter, the ear-coverts being 
of a much darker buff and larger. Differs from S. b. flavescens in having a 
much deeper yellow breast, much larger ear -coverts of a darker buff and the 
coloration of the back much darker. Most resembles S. b. melvillensis, but 
differs in having a rich yellow breast and abdomen, while the Melville Island 
bird is almost white underneath.” Type from Wantapella Swamp, Central 
Australia. 
To the preceding must now be added : 
Smicrornis brevirostris mallee, subsp. nov. 
Mallee, Victoria. 
The Mallee birds are much paler above and especially underneath than 
South Australian S. b viridescens , and are much duller than typical New South 
Wales birds. 
Another form is indicated by Captain S. A. White from the Nullarbor Plains 
where he wrote : “ These little birds come between viridescens and the interior 
bird, S. b. mathewsi. They were not plentiful — an odd pair or so seen amongst 
the mallee clumps.” 
Emphasis may be laid upon the facts that this species appears to be absent 
from Cape York and is certainly not a native of Tasmania. This suggests 
that this is a purely Australian derivative of Gerygone and that it has evolved 
independently of Wilsonavis, Ethelornis , etc., and apparently parallel to 
Pseudogerygone, which seems to have developed from the same source while 
travelling northward into New Guinea, the coloration in one altering, while 
the structural feature, the bill, has altered in the other. Here is a problem 
for genus-lumpers as to which is of the most value, coloration or structure. 
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