^^ Ixxviii ) 



the clothes in contact with it and exposed to the air, and 

 the discharge and re-absorption of a watery fluid upon such 

 surfaces would certainly lead to the ingestion of salt. j\Ir. 

 Farquharson's observation now probably received its true 

 interpretation, the arm of an armchair in the tropics being just 

 the place where salt is likely to be produced by the evapora- 

 tion of human cutaneous excretions. The dried ink observed 

 to be moistened by a skipper may have contained sodium 

 chloride or some other salt which took its place in the insect's 

 estimation, although it is perhaps more likely that some 

 gummy or sugary substance was sought. 



[While the above note was being brought forward a letter 

 from Mr. C. 0. Farquharson, written Nov. 15, was on its way, 

 containing in the following passage the very same suggestion 

 as to the object of the habit : — 



" By the way a medical man whom I met, who seemed a 

 fairly observant man, told me that in his district a certain 

 small Lycaenid was a nuisance (! !) from its habit of settling 

 on one's hands and arms to quench its thirst on perspiration. 

 I know of a small Hymenopteron [almost certainly the sting- 

 less bee Melipona] which has the same habit to a most annoy- 

 ing degree, but why I mention this is that it recalled to me 

 my theory of the object of Rhopalocampta forestan when it 

 settled on the arm of the chair, exuded the drops of clear 

 liquid and finally drank them up again. The drops might 

 easily have acquired a certain salinity." 



It is to be hoped that specimens of the Lycaenid referred to 

 may be sent home and the species identified. It is' possible 

 that the insect was a Hesperid. 



Furthermore, since the note was read I have found that the 

 habit is fully described by Mr. J. C. Kershaw in his " Butter- 

 flies of Hongkong," 1907. The following passage on p. 129 

 refers to Parnara gutiatns, Bremer and Grey : "It was 

 exceedingly common at Lo-fu-shan. One individual lit on 

 my hand and remained for at least a minute, bending the tip 

 of its abdomen as if about to lay an egg, but it deposited 

 drops of clear liquid which it eagerly sipped with its proboscis. 

 It exuded several drops in different spots, and immediately 

 sucked them dry. This and other Hesperids may occasion- 



