1896.] METALLIC COLOURS OF BIRDS. 291 
this apical band, until such a metallic feather as that of fig. 1 is 
produced. The course of development of the metallic edging of 
quill-feathers may be described in a little more detail. In order 
to illustrate this, it may be convenient to describe in a concrete 
example the differences between the sexes in the coloration of 
wings and tail. The following notes were made on a female of 
Anthreptes malaccensis and a male in nearly completed moult, but 
the characters of the adult male were checked by reference to ° 
Shelley’s ‘Monograph of the Sun-birds.’ In the male the tail was 
composed of black feathers with an edging of metallic violet, which 
was widest in the case of the two central feathers. In the wings 
the lesser wing-coverts had a broad transverse band of metallic violet, 
the median coverts a similar band of dark brown, and the greater 
coverts a longitudinal band of olive-yellow, which becomes brown 
in a completely adult male. The wing-quills themselves were 
greyish brown with olive edges. In the female the tail was dark 
brown with an edging of olive-yellow. The wing-quillsand wing- 
coverts were ashy grey with longitudinal or transverse bands of 
olive-yellow distributed in the same way as in the male. In the 
female the general contour-feathers had a broad transverse band 
of olive-yellow, while in the male most of these feathers had been 
replaced by others with transverse metallic bands. It must be 
noted that in all these cases the olive-yellow part of the feather 
has a peculiar looseness of structure visible even to the unaided 
eye. It should also be observed that the yellow edging to the 
quills is seen both in the rectrices and remiges of the female in 
this as in numerous other Sun-birds, while in the male the edging 
is replaced in the case of the rectrices by a metallic band. The 
respective distributions of longitudinal and transverse bands should 
be especially noticed, as showing how very closely the nature of 
the stripe depends upon the nature of the feather, that is upon its 
elongation. 
From the above description it is obvious that some sort of relation 
exists between the olive-yellow margins of the feathers of the 
female and the metallic margins of the feathers of the male. 
In general, we may say that there is a tendency for the feathers 
with olive margins in the female to be replaced by feathers with 
metallic margins in the male. It will be noticed that the change 
is associated with increased pigmentation in the male; in the 
median wing-coverts there is only slightly increased pigmentation 
without metallic colour. Such a tendency is very widely spread 
in the family, but the extent of replacement differs greatly. Thus 
in the species described above the olive edging of the greater 
wing-coyverts and wing-quills is not replaced by a metallic edging 
in the male. In Nectarinia famosa an olive edging in the same 
feathers in the female is replaced in the male by a metallic edging. 
In Anthrobaphes violacea the tail-coverts are edged with yellow in 
the female and in most males: according to Shelley, some males as 
an individual variation have this edging metallic. It is, however, 
needless to multiply examples. Enough has been said to justify 
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