Fraser, G., colours of Thecla.
Frere, Hookham, quoting Theognis on selection in mankind.
Fringilla cannabina.
Fringilla ciris, age of mature plumage in.
Fringilla cyanea, age of mature plumage in.
Fringilla leucophrys, young of.
Fringilla spinus.
Fringilla tristis, change of colour in, in spring; young of.
Fringillidae, resemblance of the females of distinct species of.
Frog, bright coloured and distasteful to birds.