Contributions to the theory of natural selection. A series of essays ... By Alfred Russel Wallace ...

A THEORY OF BIRDS' IESTS. 245
rich purples, and bright reds, being the most characteristic colours. The females are always obscurely
tinted, and are often of a greenish hue, not easily
visible among the foliage.
2. Manakins (Pipridm). These elegant birds, whose
caps or crests are of the most brilliant colours, are
usually of a sombre green in the female sex.
3. Tanagers (Tanagridcla). These rival the chatterers
in the brilliancy of their colours, and are even more
varied. The females are generally of plain and sombre
hues, and always less conspicuous than the males.
In the extensive families of the warblers (Sylviadae),
thrushes (Turdidae), flycatchers (Mluscicapidae), and
shrikes (Laniadm), a considerable proportion of the
species are beautifully marked with gay and conspicuous tints, as is also the case in the Pheasants and
Grouse; but in every case the females are less gay,
and are most frequently of the very plainest and least
conspicuous hues. Now, throughout the whole of these
families the nest is open, and I am not aware of a
single instance in which any one of these birds builds
a domed nest, or places it in a hzole of a tree, or underground,,or in any place where it is effectually concealed.
In considering the question we are now investigating,
it is not necessary to take into account the larger and
more powerful birds, because these seldom depend
much on concealment to secure their safety. In the
raptorial birds bright colours are as a rule absent;
and their structure and habits are such as not to re