gj . Scent-fans of a Sphinx-moth. 



serrated in the males, while it is smooth in the females. In Callidryas Philea 

 some females have the wings smooth, others serrated, but in a far less degree 

 than in the male. This may be a sort of weapon in the battles of the males 

 Whether in Papilio Grayi, P. Cleotas, P. Corcebtis, and their allies, the serrated 

 margin of the fore wings is limited to the male sex I do not know, not having 

 yet caught females of these rare species.'' 



Mr. Meldola exhibited the proboscis of the Sphinx referred to in the above 

 letter, and also the wings of a male specimen of Callidryas Argante, showing 

 the serrated margin. He remarked that he was indebted to Mr. Darwin for having 

 kindly placed the letter and specimens at his disposal. With reference to the 

 length of proboscis of Sphinx-moths, it was stated that in the British Museum 

 there is a South- American specimen of Macrosilia cluentins, the proboscis of 

 which is 23-5 centimetres (= g 1 ^ inches) long. Both Mr. Darwin ('Fertilization 

 of Orchids', 1862, p. 198) and Mr. Wallace ('Quarterly Journal of Science', Oct. 

 1867) had predicted the existence in Madagascar of a moth with a proboscis 

 sufficiently long to reach into the nectar of Angrecum sesquipedale, the nectary 

 of which orchid is from ten to fourteen inches in length. This prediction, although 

 not at present specially fulfilled with regard to Madagascar, has been since shown 

 to have a great amount of probability by the discovery of a Sphinx in South 

 America with a proboscis 25 centimetres (= 9 8 inches) in length. This specimen 

 was also captured by Fritz Miiller (see 'Nature', vol. viii., p. 223 = Ges. Schriften 

 S. 612), and has been since identified as Macrosilia cluentius (see Nature', vol. xvii., 

 p. 221= Ges. Schriften S. 639). The selective discrimination of flowers of certain 

 colours refered to in the foregoing letter appears to afford additional proof of the 

 fact that insects can distinguish colours a fact of the utmost importance to the 

 theory of sexual selection. With reference to the serrated costal margin of the 

 fore wings of butterflies, Mr. Meldola stated that this character had been shown 

 to exist in the genus Prioneris by Mr. Wallace (Trans. Ent. Soc., ser. iii., vol. iv.), 

 and in the genera Amynthia and Pyrrhosticta by Mr. A. G. Butler, but that, so 

 far as he knew, it was now made known in Callidryas for the first time. 



Mr. A. G. Butler stated that in many of the exotic Notodontidce he had 

 observed a fan-like tuft in the males. With reference to the Sphingidcc of Mada- 

 gascar, he stated that he had measured the proboscis of all the specimens in the 

 British Museum, and none of them exceeded five inches in length. Mr. Butler 

 further remarked that the whole of the Old World species of butterflies separated 

 under the Hiibnerian genus Catopsilia, the whole of the New World species se- 

 parated under the genus PJuvbis of Hiibner, all the species of the true Callidryas, 

 Boisd., and one species only of the genus ApJirissa, Butler, have the serrated 

 costa in the male sex. Aphrissa Godartiana, Swainson, although closely allied 

 to A. Hartonia, Butler, being similar in colour and pattern, but differing chiefly 

 in size and the shortness of the wings, has a strongly serrated costa, whilst A. Har- 

 tonia has the costa smooth. With regard to the object of the serrated margin, 

 Mr. Butler stated that he was disposed to accept Fritz Miiller's explanation that 

 it may be of use in the battles of the males. 



Mr. Bates remarked that in Prioneris the serrated costal margin exists in 

 both sexes. 



