LOPHASTUH. 
through isolation, the wing formula has varied and the bird is slightly larger 
mth a heavier bill, longer wing, longer tail, and stronger feet. In the wing 
the first primary is less than the seventh, the fifth longest, the fourt-h slightly 
shorter but longer than the third, which is longer than the second : this is 
about equal to the sixth, both considerably longer than the first. 
I propose to name this form Nesobaza gen. nov., type Nesobaza 
madagascariensis (Smith). It appears to be a product of isolation from the 
African branch, in which the immature plumage is retained to a greater 
extent than in Aviceda. 
Baza^ w'hich should be restricted to the type B. leuphotes Dumont, is 
superficially quite unlike the preceding in coloration and form. It is blackish- 
blue above, with white or reddish-white spots on the wings : the throat is 
black, while the breast is represented by a broad white band, followed by a 
narrow black band succeeded by brown bars. In the immature these bars 
extend to the vent, but in the senile form only a few immediately following 
the black band remain. That is, the bird has now arrived at a plumage more 
advanced than Aviceda, and has discarded the various plumages pursued 
during this development, taking on this very beautiful evolution in its first 
plumage. Phylogenetically, Baza is the most specialised form, and judged 
from colour alone it demands generic separation from the others. 
A dictum worth consideration has been written by Gurney {Ibis 1876, 
pp, 469-470) : “ I think it more convenient to use both generic names, as 
indicating two distinct groups, which are naturally separated by the totally 
different character of their immature plumage.” 
However, Baza is a much smaller bird than the others, with a compara- 
tively shorter tail, as well as more delicate in every other proportion. The wing 
formula is also remarkable : the first primary is equal to the sixth, the 
second is longer than the fifth but shorter than the fourth, while the third 
is longest. Such differences when written may not convey much, but the wing 
of Baza is comparatively a short rounded one when contrasted with that of 
any of the other species previously associated under that genus-name. 
The fourth group is the one associated with the Australian species and 
which includes Lophastur jerdoni Blyth. Many subspecies are recognised in 
this group with more than one species. These take on the mature plumage 
of the first species of Aviceda as their adult one, but their immature one 
differs little and they never have the spotted immature characteristic of 
Aviceda, Having discarded Baza, it was necessary to find a substitute and 
I at once considered Lepidogenys, which was introduced by Gould in 
connection with the Australian bird. When doing so, however, he wrote : 
“ This bird would belong to M. Lesson’s genus Lophotes, but that term 
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