Introduction; Variation. 
11 
9. Male unlike female: young female like adult female, young male 
peculiar partly; Bryobates^^^ Xenopicus: Keeler, p. 224;. 
It seems to be a very true remark of Darwin’s that these several classes 
graduate into one another. 
Ancestral characters. — At the present time much interest turns on the 
difficult question of the manifestation of the past history of the race occasional y 
to be read in the plumage of the young or in the less highly developed sex 
Among Celebesian birds the following are some of the more interesting and 
undeniable examples of ancestral indications in the young. 
The Kingfishers of the Oriental genus Pelargopsis have the lower back and 
rump blue, except in the Celebesian area, where Pelargopsis melanorhyncha and 
P. dichrorhyncha have these parts buff. The young of P- melanoi hyncha is known 
to have the parts in question blue — proof that the species was once so co oure 
(pp. 269, 270 of text). 
The Lories of the subgenera Trichoglossus typical and sitteiitees ave a 
yellow (or red) band across the under side of the wing, except in nc og ossi . 
ornatus and Psitteuteles meyeri of Celebes, P. flavoviridis of Sula, which have 
the wing uniform below. Traces of yellow, where the band should be are often 
seen in young individuals (occasionally in an apparently adult fema ej o . meye , 
and now and then in the young of T. ornatus, proving that these two species 
once possessed the wing-band (p. 126 of text). 
The Stork, Dissoiira episcopus, has no contour-feathers, but on y own, on 
the sides of the head and on the neck, though it is not to be doubted that it once 
had these parts feathered. The young has the sides of the head feathered, and 
some feathers of blackish brown are produced on the neck, but they sooii a 
out. These feathers indicate what the species was like at some period of the 
past (pp. 807, 808 of text). _ -i ^ . 
The Parrots of the genus Prioniturus have the two middle tail-featfieis 
furnished with long projecting rackets. Young birds before the first moult is- 
play attenuated projecting ends or half-formed rackets (see pi. V, figs. 1, ), 
showing, according to the argument pursued below, p. 74, an earlier stage in 
the formation of these growths. .*. 1 , a u 
The Tree Duck, Dendrocygna guttata, has round white spots on the tianKs, 
in the young these spots take the form of stripes similar to those o 
at all ages; a proof that the round spots are a recent development (p. ® 
Blackbird, Meruh cekbensis, when young is spotted like a Ihmsh (see p . . j- 
The little slate-and-vinous Hawks, Accipiter rhodogoster and sulaensis and 
Spilospizias trimtam are totally different when young, lesemblmg Kestrels 
mnLculmy. and the Pigeon, au,koplu.ps, in first plumage has no resemblance 
to the adult (an unusual oircumstanoe among Pigeons), but has the coloiation 
of the Pioeon- genus Maa-opygia. It appears hardly possible to doubt that these 
are ancesLl indications (pp. 25, 26, 660, 652 of text). 
