THE BIRDS OF AUSTRALIA. 
The above, taken in conjunction with the following measurements of 
female specimens^ should, I think, go a long way towards proving Mr. Mathews’ 
contention to be correct : 
Total 
U . /. didimay Parry Harbour, N. W.A. 
Length. 
Wing. 
Tail. Tarsus. 
Culmen, 
(not fully adult) 
„ Napier Broome Bay, 
N.W.A. (not fully 
430 
275 
225 
78 
27 
adult) 
„ Napier Broome Bay, 
N.W.A. (a very old 
bird with exceedingly 
442 
280 
230 
78 
27 
dark plumage) 
„ Macarthur River, N.T. 
465 
285 
240 
80 
28 
(fully adult, breeding) 
U. /. cruentay NuUagina, Pilbarra gold- 
field, W.A. (fully adult. 
460 
280 
225 
78 
25 
breeding) 
„ Wilson’s Inlet, near 
Albany^ W.A. (fully 
485 
300 
245 
80 
25 
adultj breeding) 
U. f. fasciatay A typical Eastern speci- 
men, according to A. 
J. North, Vol. III., p. 
483 
295 
245 
76 
28 
190, ‘Nests and Eggs ’ 
491 
309 
254 
82 
30 
(My specimens are all slightly larger.) ” 
Careful consideration of the whole of the birds available at the present 
time confirms the acceptance of the form “ didima^^ but the form “ cruenta ■ ’ 
is somewhat doubtful. It is possible, however, that the young may show 
tangible differences, and it must be emphasized that immature specimens 
seem more plentiful from some localities than others. The variation in the 
degree of the coloration of the under-surface is very perplexing;, and the 
broad and narrow bars seem due to age. Thus from one locality birds are 
obtained showing pale narrow bars and darker broad bars : these latter are 
undoubtedly, to me^ immature — that is, they present the first phase in the 
mature plumage ; succeeding moults will bring the bird into the light 
narrow-barred plumage. 
The name, Nisus australis Lesson, cannot be fixed to anything at the 
present time. In the Ibis 1881, p. 261 et seq., Gurney discussed “ Urospizias 
70 
