186 Mr. R. Hall on Birds 
As for the species P. affinis (always yellow-tipped), I 
believe it to be only a phase of the subspecies P. assimilis. 
On a previous occasion ^ I proved P. assimilis to have only 
the third quill edged with white (scarlet speculum), and the 
speculum may be yellow just as in the "third and fourth 
quill" phase. If this is really so, and I see no reason to the 
contrary, there is nothing to distinguish it from P. affinis. 
Proof will doubtless be forthcoming in support of my view, as 
specimens come in from time to time, even if the delay is as 
long as iu the finding of the specimen under review. I shall 
then place P. affinis along with P. assimilis. 
43. Cheramgeca leucosternum. Black-and- White Swal- 
low. (Hairs Key, p. 47.) 
I identified this species from one specimen obtained at 
Geraldton, 14.10.99. A second example was nesting in a 
sand-bank and incubating four egg:s. 
To others as well as myself it is surprising that this short- 
legged and small-billed bird should be so fond of burrowing. 
Apparently feebly formed, its bill must perform a movement 
similar to that noticed in certain Picarian birds that also 
tunnel. In one cliff-side a pair of Swallows had made five 
" caves '^ six inches apart in a line. The first in order 
penetrated some three inches into the firm sandy soil, while 
the others were each successively a little deeper, and the last 
was nearing completion. 
44. Petrochelidon nigricans. Tree-Martin. (HalFs 
Key, p. 47.) 
One skin was procured at Denmark on Nov. 3rd. This 
species was nesting freely in the hollows of very high dead 
timber. I had to wait twenty minutes before a bird came 
low enough to be killed with small-sized shot. 
45. Anthus australis. Pipit. (HalFs Key, p. 47.) 
A. Sk. ad. S- 27.10.99. 1^ ., 
B. Sk. imm. 29.10.99. J ^^'^^^'^^' 
My attention was particularly drawn to the colouring in 
* Proc. Linn. Soc. N. S. Wales, vol. xxiv. p. 472 (1899). 
