ACANTHYLIS CAUDACUTA. 
Australian Spine-tailed Swallow. 
Hirundo caudacuta, Lath. had. Orn. Supp., p. 57. sp. 1.— Lath. Gen. Hist., vol. vii. p. 307.— Vieill. 2nde Edit, du 
Nouv. Diet. d'Hist.Nat., torn. xiv. p. 535 ; and Ency. Meth. Orn., Part II. p. 531. 
Needle-tailed Swallow? Lath. Gen. Syn. Supp., vol. ii. p. 307.— Steph. Cont. Shaw's Gen. ZooL, vol. x. p. 133. 
Pin-tailed Swallow, Lath. Gen. Hist., vol. vii. p. 308. 
Ghcetura Australis, Steph. Cont. Shaw's Gen. ZooL, vol, xiii. p. 76. 
Hirundo pacifica, Lath. Ind. Orn. Supp., p. 58. — Vieill, 2ncle Edit. duNouv. Diet. d'Hist. Nat., torn. xiv. p. 511 ; 
and Ency. Meth. Orn., Part II. p. 529. 
New Holland Swallow? Lath. Gen. Syn. Supp., vol. ii. p. 259.— Steph. Cont. Shaw's Gen. ZooL. vol. x. p. 132.— 
Lath. Gen. Hist., vol. vii. p. 308. 
Ghcetura macroptera, Swains. ZooL 111. 2nd Ser., pi. 42.- Gould, Birds of Australia, Part II. cancelled. 
This noble species, the largest of the Hirundmidce yet discovered, is a summer visitant of the eastern por- 
tions of Australia, proceeding as far south as Van Diemen's Land ; but its visits to this island are not so 
regular as to New South Wales, and its stay in these southern latitudes is never protracted. The months 
of January and February are those in which it has been most frequently observed in Van Diemen's Land, 
where it simultaneously appears in large flocks, which after spending a few days disappear as suddenly as 
they arrived. I am not aware of its having been observed in Western Australia, neither has it occurred in 
any of the collections formed at Port Essington. 
The keel or breast-bone of this species is more than ordinarily deep, and the pectoral muscles more deve- 
loped than in any other bird of its weight with which I am acquainted. Its whole form is especially and 
beautifully adapted for aerial progression, and as its lengthened wings would lead us to imagine, its power 
of flight, both for rapidity and extension, is truly amazing ; hence it readily passes from one part of the 
country to another, and if so disposed may be engaged in hawking for flies on the continent of Australia at 
one moment, and in half an hour be similarly employed in Van Diemen's Land. 
So exclusively is this bird a tenant of the air, that I never in any instance saw it perch, and but rarely 
sufficiently near the earth to admit of a successful shot ; it is only late in the evening and during lowery 
weather that such an object can be accomplished. With the exception of the Crane, it is certainly the most 
lofty as well as the most vigorous flier of the Australian birds. I have frequently observed in the middle of 
the hottest days, while lying prostrate on the ground with my eyes directed upwards, the cloudless blue sky 
peopled at an immense elevation by hundreds of these birds, performing extensive curves and sweeping flights, 
doubtless attracted thither by the insects that soar aloft during serene weather ; hence, as I have before 
stated, few birds are more difficult to obtain, particularly on the continent of Australia, where long droughts 
are so prevalent ; on the contrary, the flocks that visit the more humid climate of Van Diemen's Land, where 
they necessarily seek their food near the earth, are often greatly diminished by the gun during their stay. 
I regret that I could ascertain no particulars whatever respecting the nidification of this fine bird, but 
we may naturally conclude that both rocks and holes in the larger trees are selected as sites for the 
purpose, as well as for a roosting-place during the night. Before retiring to roost, which it does imme- 
diately after the sun has gone down, the Spine-tailed Swallow may frequently be seen, either singly or in 
pairs, sweeping up the gullies or flying with immense rapidity just above the tops of the trees, their never- 
tiring wings enabling them to perform their evolutions in the capture of insects, and of sustaining them- 
selves in the air during the entire day, without cessation. 
The sexes offer no perceptible difference in their outward appearance ; but the female, as is the case with 
the other members of the family, is a trifle smaller than her mate. 
Crown of the head, back of the neck, and ear-coverts deep shining green strongly tinged with brown ; a 
small space immediately before the eye deep velvety black ; band across the forehead, throat, inner webs of 
the secondaries nearest the back, a patch on the lower part of the flanks and the under tail-coverts white ; 
wings and tail deep shining green, with purple reflexions ; centre of the back greyish brown, becoming 
darker towards the rump ; chest and abdomen dark clove-brown ; bill black ; feet brown. 
The figures are those of the male and female of the natural size. 
