[page] 97

On Birds' Nests and their Plumage; or the Relation between Sexual Differences of Colour and the Mode of Nidification in Birds. By ALFRED R. WALLACE, F.R.G.S., F.L.S.

The author pointed out the hitherto unnoticed fact, that whenever female birds resembled the males in being adorned with gay and conspicuous colours, their nests were so placed or so constructed as to conceal the sitting bird. He showed that this generalization was supported by a vast number of facts in all the chief groups of birds, while the exceptions were few and unimportant, and concluded by pointing out its correspondence with the general principle of protection in modifying colour, and by arguing that the whole of the phenomena could be well explained on the theory of the preservation of useful variations.