52 
Birds of Celebes: Falconidae. 
islands they quite disappear. In India and Burmah the stripes are broad and 
take in some of the web of the feather on either side of the shaft; in Ceylon, 
Siam, Malacca and Sumatra the stripes are generally narrower, a further de- 
crease is seen in specimens from Java, Sumbawa, Sumba, Flores, Borneo and 
the Philippines, where the streaks appear to be confined to the shafts, which 
are very distinct and black, and Javan specimens were named intermedins by 
the late J. H. Gurney; a little more East a still further decrease in the dark 
shaft-streaks is to be seen in specimens from Sangi, Celebes, Sula, Halmahera, 
Obi major, Amboina, Burn, Timor, and North Australia, where the dark shaft 
lines are, as a rule, thin and scanty, or are quite absent, leaving the head, 
neck and breast pure white; in New Guinea and the surrounding islands. New 
Ireland, Solomon Islands and Aru, these parts are, apj)arently, in general, pure 
white, and this most eastern form of the species has received the name girrenera 
from Vieillot. But the species is so plentiful throughout its range, and the 
transition from the broad-striped specimens of India to the white ones of New 
Guinea is so gradual and regular that it is impossible to draw any distinct lines 
of demarkation between specimens from neighbouring localities; and any geo- 
graphical sections of the whole which have been called by distinct names are, 
by definition, only subspecies, or even subsubspecies. 
In how far is it practically profitable to distinguish local sections of this 
species by name, and what form of nomenclature is convenient? According to 
the most prominent present-day definition of ornithologists, species are well- 
differentiated groups of individuals which are not connected with one another 
by means of a series of intermediate intergrading forms, whereas subspecies 
are interconnected by such a series of intermediate forms. Just as a genus is 
always known under a single name, so also a species should always be known 
under a binomial, and subspecies under trinomials. In the present case of 
Haliastur indiis^ it seems advisable to recognise at least the two extreme forms 
of the species, as subspecies, viz: the typical race of India with the broadest 
stripes, and that of New Guinea without any stripes. Unhappily, modern rules 
of nomenclature make no provision for distinguishing as a subspecies the local 
race first described, and we are compelled to speak of both the species as a 
whole, and of the typical subspecies, as Haliastur indus (Bodd.). Granting that 
it be worth the trouble to recognise subspecies at all by name, it is certainly 
adventageous that one and all should be spoken of under trinomials in order to 
distinguish them from species, of which they only represent a part. This might 
readily be done by strictly confining the original binomial to the species, as at 
present defined, and then adding the word typicus to the typical subspecies 
first described, but it is not yet advisable to employ this method, inasmuch as 
— until some rule of nomenclature be made to prevent this result — the name 
of the writer, who appended the word typicus to the originally described race, 
would be likely to be quoted by any one writing down the trinomial hereafter 
and the name of the true author overlooked. In referring to such subspecies 
