Ɛpsilon

From A. G. Butler   31 March 1879

10 Avington Grove, Penge

31st. March 1879

Dear Dr. Darwin

You will be glad to hear that I have been successful in obtaining the Post of Assistant-Keeper in the Zool. Dept. of the British Museum, for which you were so kind as to give me a testimonial.1

I have lately (i.e. for the last year or two) had an opportunity of studying the Heterocerous Lepidoptera much more closely than formerly, and I find the scent-fans spoken of by Fritz Müller extremely common, particularly upon the legs of moths: strigillating organs occur in all parts in the form of drums, bladders, rasps, and in all sorts of forms: most of the Zygænidæ have a drum-like apparatus at the base of the abdomen, somewhat as in Cicada; this is probably an organ of sound.2

The Genus Sphingomorpha, among the Noctuites, has a bladder-like organ upon its legs which are also provided with enormous radiating fans of hair.3

For anybody who had the time to devote to the study of these structures and their modifications in allied species, there would be an almost endless field for interesting research: perhaps after all no new facts would be brought to light however.

With many thanks for favours past, and the hope that I may yet live to be in some measure useful to you or at anyrate to the Science which you have done so much to advance | Believe me to be | Very sincerely yours | Arthur G Butler

1
CD’s testimonial has not been found, but see the letter to A. G. Butler, 20 February [1879].
2
Heterocera was a former higher taxonomic classification that included all moths. Butler probably meant to refer to stridulating organs; some insects, like crickets and grasshoppers, stridulate by the use of specialised organs on their wings, legs, or other body parts, which they rub against each other to produce sound. Fritz Müller’s ‘Notes on Brazilian entomology. Odours emitted by butterflies and moths’ (F. Müller 1878a) had been read at the meeting of the Entomological Society of London on 5 June 1878. In the discussion following the reading, some scepticism had been voiced as to whether the organs described were really scent organs (see Correspondence vol. 26, letter from Raphael Meldola, 13 June 1878). Zygaenidae is the family of burnet and forester moths. Male cicadas (family Cicadidae) make sounds by vibrating the tymbal, a drum-like structure in the abdomen; some moths also possess tymbals in the sternal region of the abdomen. For genera and species included by Butler in the Zygaenidae, see A. G. Butler 1875.
3
Sphingomorpha is the genus of fruit-piercing moths in the family Erebidae.

Please cite as “DCP-LETT-11963,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-11963