With parrots, which likewise build in holes, we find analogous cases: in most of the species both sexes are brilliantly coloured and undistinguishable, but in not a few species the males are coloured rather more vividly than the females, or even very differently from them. Thus, besides other strongly-marked differences, the whole under surface of the male King Lory (_Aprosmictus scapulatus_) is scarlet, whilst the throat and chest of the female is green tinged with red: in the _Euphema splendida_ there is a similar difference, the face and wing-coverts moreover of the female being of a paler blue than in the male.[219] In the family of the tits (_Parinæ_), which build concealed nests, the female of our common blue tomtit (_Parus cæruleus_) is “much less brightly coloured” than the male; and in the magnificent Sultan yellow tit of India the difference is greater.[220] Again in the great group of the woodpeckers,[221] the sexes are generally nearly alike, but in the _Megapicus validus_ all those parts of the head, neck, and breast, which are crimson in the male are pale brown in the female. As in several woodpeckers the head of the male is bright crimson, whilst that of the female is plain, it occurred to me that this colour might possibly make the female dangerously conspicuous, whenever she put her head out of the hole containing her nest, and consequently that this colour, in accordance with Mr. Wallace’s belief, had been eliminated. This view is strengthened by what Malherbe states with respect to _Indopicus carlotta_; namely, that the young females, like the young males, have some crimson about their heads, but that this colour disappears in the adult female, whilst it is intensified in the adult male. Nevertheless the following considerations render this view extremely doubtful: the male takes a fair share in incubation,[222] and would be thus far almost equally exposed to danger; both sexes of many species have their heads of an equally bright crimson; in other species the difference between the sexes in the amount of scarlet is so slight that it can hardly make any appreciable difference in the danger incurred; and lastly, the colouring of the head in the two sexes often differs slightly in other ways.