i;)ll] The Scents of Butler Mas. 73 



WEEKLY EVENING MEETING, 



Friday, March 3, 1911, 



The Right Hon. Sik Henry Bukton Buckley, B.C. M.A., 

 Vice-President, in the Chair. 



F. A. DiXEY, Esq. M.A. M.D. F.R.S., Fellow of Wadham 

 College, Oxford. 



The Scents of Butterflies. 



Among all the country sights of Spring, Summer and early Autumn, 

 I suppose there is none more familiar than that of the common white 

 hutterflies. They are to be seen, as we know, everywhere ; haunting 

 woods, hedgerows, lanes and gardens, crossing heaths and meadows, 

 and visiting at times not only parks and squares, but even streets in 

 the heart of London. Of these insects there are, in this country, 

 as is no doubt known to many of you, three especially abundant 

 kinds. One of these is the large Cabbage AVhite ; the other two 

 species are smaller. These two latter kinds are much alike when 

 seen on the wing ; but on a closer view they are easily distinguished, 

 the most obvious mark of difference being the presence in one of 

 them of greyish-green streaks, following the course of the so-called 

 " veins " or " nervures," on the under surface of the hind wing. 

 From this character the form in question gets its common name of 

 the " Green-veined White." If anyone will capture a male Green- 

 veined White (easily distinguished from the female by the much 

 shghter spotting of the male's upper surface), and will brush the 

 upper surface of the fore or hind wing with a camel-hair pencil, he 

 will become conscious of a strong agreeable odour like that of the 

 so-called " lemon-plant." On further examination he will find that 

 this perfume emanates from the wings of the butterfly, and is strongly 

 perceptible on the brush with which the wings were rubl)ed. The 

 rubbing process has, of course, dislodged large quantities of the minute 

 scales with which the wings of this insect, like those of butterflies 

 and moths in general, are clothed ; and these dust-like scales, adher- 

 ing to the brush, have in some way or other carried with them the 

 characteristic odour of the butterfly. A similar scraping or rubbing 

 of scales from the under surface of the wings does not emit the 

 odour, nor is it found in association with any scales from either 

 surface of the female. 



We find, then, that in this butterfly the perfume attaches to the 

 scales in one particular situation, namely, the upper surface of the 

 wings of the male insect. This fact obviously suggests that we 

 should examine these particular scales in order to find out whether 

 they present any differences from the scales which appear to be 



