BORNEAN CRESTED FIREBACK 139 



paler in the primaries. The tail-feathers are quite variable ; sometimes the two central 

 pairs and the longest tail-coverts are heavily freckled or mottled with dark chestnut — 

 though this is always subordinated to the black (the reverse pattern of the anterior 

 dorsal surface) — while again there will be hardly a trace of the lighter colour, all the 

 rectrices being uniformly black. 



The entire lower breast, abdomen, flanks and anterior thighs sooty black, broadly 

 margined all around with white. In the disintegrated, downy feathers of the lower 

 abdomen the white margin encroaches upon the black centres, turning them impure 

 brown and restricting them to a small central area. The under tail-coverts and the 

 posterior sides of the thighs are dull black, tipped more or less strongly with dark 

 chestnut. 



Irides red ; legs and feet yellowish-white ; facial skin blue, duller than in the 

 male; mandibles horny-white; spurs sharp but abortive, only about 3 mm. in length. 

 Weight 3i lbs. Length, 580; extent, 778; bill from nostril, 18; wing, 258; tail, 190; 

 tarsus, 89 ; middle toe and claw, 50. 



Natal Down. — Four day old chick. Warm rufous on crown and nape, becoming 

 black on scapulars and entire back. Rufous buff bar across centre of wing. Latero- 

 dorsal longitudinal bands almost obsolete. Face pale rufous, a black line obliquely 

 back from the orbit across ear-coverts, ending just beyond. Chin, throat and belly 

 buffy white, a strong orange-buff tinge across breast and down sides and flanks. 

 Primaries just appearing at the tips of the sheaths. 



A Three Weeks' Old Chick is much the same, except for great development 

 of wings which cover the entire body, extending well beyond the tail. Coverts and 

 flight-feathers dark brownish black, the former with buffy tips and a jet-black 

 sub-terminal band. The inner secondaries with very slight buff edgings, other flight- 

 feathers unmarked. At this age, seven primaries and eight secondaries are functional. 

 Primary No. 8, although over 13 mm. in length, is still ensheathed, and Nos. 9 and 10 

 are as yet invisible. 



The tail-feathers have just broken their sheaths, bearing aloft the pale rufous 

 down. 



Juvenile Plumage. — In a chick of seven weeks — four weeks older than the one 

 above — considerable change has taken place. The entire body and the rear crown are 

 clad in short but fairly complete juvenile plumage, while the head and neck are still 

 downy. 



On the rear crown, sharply limited on all sides, on or just anterior to the place 

 where the adult crest will appear, is a dense triangular patch of loose chestnut feathers, 

 somewhat shaded with black. The entire hind neck is downy, but the mantle and 

 back are densely covered with a growth of rich chestnut, black mottled feathers. At 

 this stage the sexes are distinguishable, the males having the dorsal plumage much 

 darker than the hens. 



The eight primaries are growing strongly, the eighth still lagging far behind, about 

 half as long as the rest, while Nos. 9 and 10 are just detectable as two minute sheaths 



