From Raphael Meldola   13 June 1878

21 John St. | Bedford Row, | London W.C.

June 13/78

My dear Sir,

I am much obliged for your offer to lend me Weismann’s essay on Daphnidæ which I shall be glad to read although I cannot pretend to any special knowledge of the Crustacea.1 I want however to trace the steps which have led the author to believe in sexual selection as a cause for the colours of butterflies.

Fritz Müller’s paper on the “Odours emitted by Butterflies” was duly read at the last meeting— Bates seemed rather in doubt at to whether F. M. had conclusively demonstrated that the “fans”, “brushes” &c in Lepidoptera were really scent organs. I think there can be no second opinion about this after reading F. M’s former papers which he was good enough to send me.2 We had also an interesting paper by Peter Cameron “on the larvæ of Tenthredinidæ with special reference to protective resemblance.3 I exhibited Dr. Zacharias photographs of Pterochroza—4 it appears that in one of the specimens the forewings had been broken off & were stuck on again hind part before so that the neuration was somewhat “mixed”:— Thus:—

diagram

Accompanying Fritz Müller’s letter & paper there was an interesting specimen which will be duly described in our “Proceedings”. It was the elongated nectary of a sp. of Hedychium which had caught a Sphinx-Moth by its proboscis— this frequently happens according to F. M. What a striking argument against the teleological theory of adaptations!5

Yours very sincerely, | R. Meldola.

1
In his letter of 12 June [1878], CD had offered to send Meldola August Weismann’s third essay on Daphnidae (part of Weismann 1876–80). The essay explained the acquisition of bright colours in these crustaceans through sexual selection and posited a similar explanation for bright colours in butterflies.
2
Fritz Müller’s ‘Notes on Brazilian entomology. Odours emitted by butterflies and moths’ (F. Müller 1878), sent with his letter to CD of 5 April 1878, was read at the meeting of the Entomological Society of London on 5 June 1878. Henry Walter Bates, the president of the society, remarked at the meeting that ‘when collecting on the Amazons he had often observed the strong odour of vanilla emitted by certain butterflies. Without a more complete examination of the evidence, however, he was not prepared to admit that the tufts of hair or manes on the wings, &c., of butterflies were scent-secreting organs’ (Transactions of the Entomological Society of London (Proceedings) (1878): xxvii). In 1877, Müller had published on sexual selection in Brazilian butterflies and on hair-tufts, felted spots, brushes, and similar structures in male butterflies (F. Müller 1877a and 1877b).
3
Cameron 1878; Tenthredinidae is the largest family of sawflies.
4
CD sent Otto Zacharias’s photographs of leaf-mimic katydids to Meldola with his letter of 17 April 1878. For details, see the letter from Raphael Meldola, 3 May 1878 and n. 2; for a report of Meldola’s exhibition of the photographs at the meeting, see Transactions of the Entomological Society of London (Proceedings) (1878): xxiv.
5
A brief description of Müller’s specimen appears in Transactions of the Entomological Society of London (Proceedings) (1878): xxiv. Hedychium is the genus of ginger lilies; sphinx-moths belong to the family Sphingidae.

Please cite as “DCP-LETT-11553,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-11553