Mr. R. Meldola on Evolution. 155 
XVIII.—Entomological Notes bearing on Evolution. 
By RapHarEL MELDOLA, Sec. Ent. Soc. 
In 1871, when working at the subjects of “‘ mimicry” and 
protective resemblance,’ Mr. Darwin was so good as to send 
me for perusal a letter which he had received from Fritz 
Miller, then in St. Catharina, Brazil. As this letter contains 
many entomological observations of interest, I have thought it 
advisable to take steps to secure their being placed upon 
record in a permanent form; and, with the permission of Mr. 
Darwin, I have selected extracts which I beg to make known 
in the present paper, together with other observations from 
various sources which tend to throw light on subjects con- 
nected with the descent theory. 
Sounds made by Butterflies. 
Mr. Darwin has already recorded * the sound produced by 
the South-American butterfly, Ageronia feronia, which is 
stated to make “a noise like that produced by a toothed 
wheel passing under a spring catch, and which could be heard 
at the distance of several yards.’’ With reference to the 
object of this sound Mr. Darwin states J, “‘ At Rio de Janeiro 
this sound was noticed by me only when two were chasing 
each other in an irregular course, so that it is probably made 
during the courtship of the sexes.” With regard to this 
insect Fritz Miiller writes, ‘I told you some time ago that I 
had not yet seen it here; but lately I have caught two speci- 
mens belonging to two species, and I have seen in the collec- 
tion of a friend of mine a third specimen of a third species. 
One of these specimens had been observed for many days by 
my children flying around some orange-trees near my house ; 
it frequently alighted on the putrefying fruit on the ground, 
on the juice of which it seemed to feed. My children never 
heard any noise produced by it, neither did I; and this seems 
to confirm your view that the noise is made only during the 
courtship of the sexes.”’ 
I may add that our common Vanessa Jo is stated to make 
a faint hissing sound{; but the precise conditions under which 
this noise is produced require further observation. 
* Journal of Researches, 1845, p. 33. On the sound-producing appa- 
ratus see E. Doubleday in Proc. Ent. Soc., March 3, 1845. See also a 
pe by Mr. A. H. Swinton, “On an Organ of Hearing in Lepidoptera,” 
nt. Mo. Mag., Nov. 1877. 
+ Descent of Man, 2nd ed. p. 307. 
t Rey. J. Greene, Trans. Ent. Soc. new series, vol. ii. p. xeviii, and 
Mr. Hewitson, ibid. vol. iv. p. ii, The sound-producing structure has 
been figured by Mr. Swinton, Ent. Mo. Mag., Jan. 1877. 
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