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Darwin Correspondence Project

From T. A. Edison   7 December 1877

Menlo Park N. Jersey U.S.A.

Dec 7 1877,

Charles Darwin Esqr

Dear Sir,

Several small green colored insects were caught by me this summer having come into my laboratory windows at night. The peculiarity of these insects are that they give off when Gathered, an exceedingly strong smell of Napthaline.1 No difference can be detected between the odor from the insect and the crystals of Napthaline except that the odor from the insect is much more powerful. I suppose this odor is used as a means of defence like that from the Skunk.

I thought this would interest you if you were not already aware of such an insect. I could procure some next summer and send by mail if you desire them

Yours | Thomas. A. Edison | Telegraph Engineer


Edison probably refers to a green lacewing (Chrysopa sp.; see Kritsky 1993, p. 81). Naphthalene is an aromatic hydrocarbon with a distinctive odour of mothballs, in which it is the main ingredient.


Kritsky, Gene. 1993. Thomas Edison’s entomological pursuits and his correspondence with Charles Darwin. American Entomologist 39: 79–82.


Offers to send green insects that give off a powerful odour of napthalene.

Letter details

Letter no.
Thomas Alva Edison
Charles Robert Darwin
Sent from
Menlo Park, N.J.
Source of text
DAR 163: 1
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 11271,” accessed on 26 September 2021,