BORNEAN CRESTED FIREBACK I4I 
full grown but unshed. The outer secondary is still unshed; the second is full grown. 
The next five are new, more recent as we proceed inward, until the fifth is merely a 
short unbroken sheath; the next inner six are unshed. 
The persistence of the first secondary is very remarkable. Not only in these birds, 
but in another of seven months, which in many respects is full plumaged, the right 
outer secondary still persists, the left having just been shed. The succeeding nine 
secondaries are full grown, the next three being, like No. 1, still old, unshed 
feathers. 
Another focus of delayed growth is found in the central rectrices. In the three 
males just described, the three inner pairs of tail-feathers are still unshed, juvenile 
feathers, although a@// of the others are new and well advanced. In all there is a 
regular gradation in growth from the outer to the fifth pair, the latter being only 
25 or 30 mm. beyond the tip of the sheaths. The narrow, brown, worn tips of the 
three inner pairs extend some 50 mm. beyond the longest new feathers, giving all 
the birds a most curious appearance. At this age the spurs are about 5 mm. in length, 
sharp, thin, triangular scales. 
The measurements of the five stages of growth in male birds which I have 
described, together with those of the adult male are as follows, tabulated for easier 
comparison. 


Bill from Middle Toe 
nostril Wing Tail Tarsus and Claw 
Four day chick . ; : : ; : . 6 ZO — 23 16 
Three weeks chick . : : : j . 8 78 IO 25 18 
Seven weeks juvenile ‘ : ¢ : ' II 129 66 35 25 
Older full juvenile . : . , ‘ s 15 210 137 68 46 
Transitional, juvenile to first year . ‘ : 18 235 Juv. 168 86 51 
New 127 
(Not full grown) 
Adult male... : 7 é : ; ‘ 21 271 253 III 58 





IMMATURE FEMALE.—The sexes are well marked first in the early juvenile plumage 
when the mantle and breast begin to show a preponderance of dark colour in the male, 
or rufous in the female. The head, nape, mantle and lower throat in the latter sex 
moult into almost solid chestnut, shading into white on the upper throat and chin. 
The black ocelli or sub-terminal band on the scapulars and wing-coverts are much 
more conspicuous than in the male, owing to their pale, rich chestnut setting. The 
secondaries also show the chestnut mottling much plainer in the female sex. 
The ventral surface of the immature female is more definitely coloured, the regular 
pattern showing dark brown centres, broad white lateral fringes and an equally 
well-marked terminal band of chestnut. This pattern extends well down the sides 
of the body, but on the lower breast the white begins to eclipse all other hues, until 
on the belly it wholly replaces them. 
One young female shows the inner six pairs of rectrices still unshed, while the 
two outer pairs are represented by tiny sheaths. In another the three central pairs 
are still unshed. All show the same gradual moult from outside inward as in the 
males. 
