WCP4676

[1]

Old Orchard,

Broadstone,

Wimborne.

Feb[ruar]y. 17th. 1910

Dr. Karl Jordan¹

Dear Dr. Jordan

I want the names of a few butterflies which I dare say you can give me without trouble. I am writing a chapter on Colour, and I want the names of those species of butterflies which have changing phosphorescent glows. I know of 3 only — but you probably know of many more. One is Papilio catord[?] (G.R. Gray)²the red spots on hind is chang[ed] to intense luminous [word illeg.] [2] when viewed very obliquely from the head.

Another is a rare Ornithoptera from the Philippines — the yellow on the hind wings of which changes in a similar manner to this O.megallanus?

The third is a wonderful little genus of Erycinidiae which Bates³ got at Ega⁴ (I believe) in which the whole upper surface is if I remember a buff-yellow, but which changes to the phosphorescent glow when viewed obliquely.

I was immensely struck by these 3 butterflies because they [3] seemed to me to go beyond any colours even in birds or beetles.

Will you kindly give me the correct names of these I have referred to — also, how many other species you know of in these or in other groups — also, do you agree with me that the appearance is best described as phosphorescent or opalescent. I used to use the latter term, but last summer looking closely at a very fine glow worm, it struck me at once that the Papilio [4] (the only one I have that shows it —) changed into such a luminosity, — as if it gave out light rather than reflected it. Has any one written on these changes of colour?

Yours very truly | Alfred R. Wallace [signature]