99 



tribution, and from these redder forms curtisii may have sprung. 

 Indeed, the prevailing tone of colour of the forms found in the various 

 districts embraced in the area covered by the species appears to lend 

 some support to such a theory. Thus the specimens from Asia 

 Minor (the south-easterly extremity of its range) are all of the greyish 

 clay-coloured form ; in Central Europe a distinct reddish shade is 

 noticeable in many examples ; reaching Southern Britain we find this 

 intensified ; in the north of Ireland, Denmark, and parts of Scotland 

 many individuals are of a uniform brick-red colour ; and further 

 north, in Elgin, Sutherland, &c., a fair percentage of the claret- 

 coloured curtisii variety are found ; while in Orkney (the north-west 

 limit of its range) the species is represented only by an extremely 

 dark form of this variety. If we were shown a series of these 

 Orkney examples beside one of the Asia Minor type, without any of 

 the intermediates to connect them, we might well believe that they 

 were distinct species, and in this remarkable divergence of form 

 we probably have a good example of long-continued progressive 

 variation. 



Is Cold the Cause of Melanism in Scotch Specimens of 

 Triphaena orbona, Hufn. (comes, Tr.) ? 



By J. W. TuTT, F.E.S. Read May \\th, 1896. 



At the last meeting of the Society it will be remembered that 1 

 took exception to the following statement in Mr. Adkin's paper : — 

 " I consider that all the evidence points to cold being the chief 

 factor in the darkening of the species Triphcena orbona {comes) in its 

 northern localities." 



It may further be remembered that when I suggested that this theory 

 (viz. that cold was probably the cause of the melanism in T. orbona) 

 could not be sustained, because Moray was one of the mildest dis- 

 tricts. in Scotland, I was met with the statement that there "was 

 something peculiar in the atmosphere of those parts of Scotland that 

 produced these dark forms, for the sallows were some six weeks later 

 than in England." This is the sort of statement that one cannot 

 meet very well offhand, and 1 did not attempt to do so. As, however, 

 the actual conclusions of Mr. Adkin's paper hinge entirely on this 

 point, I think you will agree with me that the truth of the matter is 

 worth seeking; for statements and deductions based on false data 

 not only cease to be science, but mislead others who are anxious to 

 do good work. 



I therefore determined to look into the matter ; and turning over 

 the pages ofthe" Intelligencer" for 1858, 1, by chance, came across the 

 following on page 3, which suited my purpose admirably. It is from 



