HIRUNDAPUS. 
remarkably distinct from eacli other as well as from other forms. Oates 
proposed the genus Rhaphidura for one, and fearing criticism included the 
other. The non-recognition of his genus shows his fears were well grounded, 
as it is a very distinct and valid genus and would only be lumped by careless 
or prejudiced workers. The type of his genus, Bhaphidura, was Acanihylis 
leucopygialis Blyth, and this is a small bird, of blue-black coloration, with 
light upper tail-coverts, which are so long as almost to hide the tail, which 
is short with the spines proportionately very long, while the feet are small 
and weak. 
The other species associated with it was named Acanihylis sylvatica 
by Tickell, and is the smallest of the group : the wings are not so long as in 
the preceding, while the tail is long and rounded, with the projecting spines 
very short, and the feet minute. The coloration is very different from that 
of the preceding, especially the under-surface. I introduce for it the new na*me 
Indicapus. 
Type Indicapus sylvaticus (Tickell). 
The last form I will discriminate is perhaps more interesting than any 
of the others, as it suggests the keynote to the solution of the evolution of 
the Spine-tailed Swifts. This is Chcetura grandidieri Schlegel, which lives at 
Madagascar. Superficially in every detail, save its tail, it is a “ Collocalia 
of the Zoonava group. It absolutely agrees in detail as to coloration and, 
moreover, has the nostrils placed as in the “ Collocalia ” group, not as in the 
“ Chcetura ” typical series. Further, the second primary appears to be longest, 
which is a character of the former, but not of the latter. The superficial 
resemblance is so great that it possesses a MS. name showing its determination 
as a “ Collocalia’^ A natural classification will almost certainly prove that 
is its nearest relationship and that the evolution of the Spine-tail is more 
recent than the acquisition of plumage coloration. To initiate this quest, 
I propose to give it the new generic name 
ZOONAVENA 
with type Zoonavena grandidieri (Schlegel). 
The tail-feathers are stiff, but the needle-points are quite minute. 
As noted above, Ridgway introduced the new genus Mearnsia for Chcetura 
picina Tweeddale. This species from the Philippine Islands stands alone 
in coloration and form : the wings being exceedingly long and the tail 
exceedingly short. 
The peculiar distribution of these Needle-tails may be here appended. 
Hirundapus and Pallenia are Asiatic, while Streptoprocne is American. 
These constitute the large series which agree generally in coloration and size. 
Chcetura restricted is American, and though the species are somewhat 
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