4 
Birds of Celebes : Falconidae. 
dress assumed in the nest itself. Longitudinal streaks on the feathers of birds appear 
to represent a more original, less highly differentiated plumage than do cross-bars; 
this is shown by the fact that almost all birds of pi’ey, which when adult acquire a 
cross-barred under-side, have this region streaked or drop-marked when immature. 
If Gurney’s view, that the pale, streaked specimens of SpUornis are in the 
second plumage, he correct, the curious case would he seen of a species regularly 
reverting from a higher stage of dress to a lower one and, subsequently, re-acquiring 
the more highly differentiated coloration. 
As pointing to the prohabdity that both albescent, streaked individuals and also 
dark, spotted ones exist from the nest in the case of Spilornis, Colonel Lcgge iioints 
out that of the Booted Eagle (Xisaekis pmnatus) both dark and h'ght youno- ones 
have been taken out of the same nest; but the case is not strictly a parallel to that 
QiSpdm-ms, inasmuch as N.pmnatus has two different phases of adult dress, a light 
and a dark one, and, when dimorphous pairs of young ones have been found, they 
are said to be sprung from a h'ght male and dark female, or vice-versa (B. Ceylon, 62). 
The albescent plumage is found in both sexes. 
Skeleton. Length of cranium . 
77.5 
mm 
'Length of fibula 
Greatest breadth of 
cranium 42.0 
» » tarso-metatarsus . 
. 76.0 » 
Length of humerus . 
97.0 
» 
» » sternum 
. 61.0 » 
» » ulna . . . 
110.0 
» 
Greatest breadth of sternum 
. 35.5 » 
» » radius . . 
105.0 
» 
Height of crista sterni . . . 
. 13.5 » 
» » manus . . 
87.0 
» 
Length of pelvis 
70 n 
» » femur . . 
65.0 
» 
Greatest breadth of pelvis . 
. 31.5 =. 
» » tibia . . . 
105.5 
» 
(Siao, Sangi in Mus. Berol. XVII.) 
Nidifleation. Unknown. 
Distribution. Celebes. South Peninsula (W allace a 7, Guillemard a 14, Platen a 13, Weber 
a 17, etc.); Central Celebes — Luwu Distr. (Weber a 17, P. & E. Sarasin a 20); 
^E. Peninsula Kendari (Beccari a 7); E. Peninsula (Xat. Coll, a 21); N. Peninsula 
cfe); Talissi Id. (Hickson a 15); Lembeh Id. 
(JNat. Coll, in Dresd. Mus.); Siao — known only from skeleton (Meyer a XVI). 
2. Spilornis rufipectus sulaensis (Schl.). 
d. Circaetus sulaensis (Ij Schl., Valkv. Xed. Lid. 1866, 38, 72, pi. 23, figs 4—6- (2) G,-iv 
HL. 1869 I, 15. 1 7 a ■,( / yjriciy, 
e. SpUornis sulaensis flj Wall. Ibis 1868, 16; f2J Sharpe, Cat. B. 1874, 1, 292- f3) Gurnev 
Ibis 1878, 102, f4J id. Diurn. B. of Prey 1884, 17; f5J Sharpe, Ibis 1893, 552. 
f. Circaetus rufipectus sulaensis (1) Schl., Mus. P.-B. Rev. Accip. 1873, 114. 
Figures and descriptions. Schlegel d I; Sharpe e 2. 
Diagnosis. Wing relatively shorter than in the typiced 8. rufipectus (see table); under-side 
of qmUs gr-eyish white, passing into blackish at the distal ends, and crossed by three 
or four well-marked bars of blackish, much narrower than those of the typical form. 
These bars do not coalesce on the basal half of the quills in the same manner as in 
that form, but pass separately across the wing. 
Distribution. Sulalslands, SulaBesiandSulaMangoli(Allen Bernstein & Hoedt cJ, eJ). 
In the Leyden Museum are seven specimens — 3 ad., 3 9 ad. and 1 Q juv. 
albescent from Sula. The males have the breast paler; on the lower breast and 
