conspicuous parts; for those kinds which habitually display the underside
of the wing have this side gaudily coloured, and this is not so in the
reverse case. I daresay you will know that the males of many foreign
butterflies are much more brilliantly coloured than the females, as in the
case of birds. I can adduce good evidence from two large classes of facts
(too large to specify) that flowers have become beautiful to make them
conspicuous to insects. (425/2. This letter is published in "A Country
Schoolmaster, James Shaw." Edited by Robert Wallace, Edinburgh, 1899.)

(425/3. Mr. Darwin wrote again to Mr. Shaw in April, 1866:--)

I am much obliged for your kind letter and all the great trouble which you
have taken in sending to all the various and interesting facts on birds
admiring themselves. I am very glad to hear of these facts. I have just
finished writing and adding to a new edition of the "Origin," and in this I
have given, without going into details (so that I shall not be able to use
your facts), some remarks on the subject of beauty.


LETTER 426. TO A.D. BARTLETT.
Down, February 16th [1867?]

I want to beg two favours of you. I wish to ascertain whether the Bower-
Bird discriminates colours. (426/1. Mr. Bartlett does not seem to have
supplied any information on the point in question. The evidence for the
Bower-Bird's taste in colour is in "Descent of Man," II., page 112.) Will
you have all the coloured worsted removed from the cage and bower, and then
put all in a row, at some distance from bower, the enclosed coloured
worsted, and mark whether the bird AT FIRST makes any selection. Each
packet contains an equal quantity; the packets had better be separate, and