188 THE entomologist's record. 



more transparent, and perhaps of a purer white than even S. menthastri 

 shows in its southern haunts, whilst the male is of a brown so deep 

 that it is sometimes termed black, and quite unapproached by the 

 gTound colour of any S. luhricipeda ; nevertheless, in Ireland under 

 ordinary and in England under pathological conditions, there is a partial 

 assumption of the normal buff coloration of the group. 



From these facts a simple deduction or two may be drawn. I am 

 of opinion that the ancestral type of this group was buff-coloured, be- 

 cause this is the coloration to which under special conditions of environ- 

 ment, &c. all the species revert. I take it also that this ancestral type 

 was accustomed to a damp and moist climate, for it is in such a climate 

 that the buff coloration appears in all the species ; the white S. men- 

 thastri of southern, eastern, and middle England becomes buff in the 

 moister districts of Ireland, Scotland and northern England ; the pale 

 buff of the S. luhricipeda that we meet witli in our drier areas becomes 

 deeper in tint in the same areas ; whilst in the more isolated and moister 

 jjarts of our islands where S. mendica is found the deep brown of 

 British specimens retains the ancestral coloration ; even the white S. 

 urticae tends there to become cream-coloured in many specimens. 



The facts, that in S. menthastri both sexes assume a buff coloration in 

 these moist areas, that in S. hihricipeda the sexual difference of colours 

 is less strongly accentuated there, whilst in S. mendica, though the 

 males become buff, the females are often much less white than those 

 from England, all tend in the same direction, and point to a time when 

 the immediate progenitor of these species had a buff male and female 

 which were suited to its then environment ; and after the differentiation 

 of our present species we see how possible it is for natural selection and 

 climatic changes to have produced the differences we now know so Avell. 

 One other thought suggests itself. This extreme sexual differenti- 

 ation in S. mendica is probably of very recent origin. That it is recent 

 (as such things go) is certain from the occurrence of the ancestral form 

 in local areas distributed from Ireland to the Caucasian mountains ; but 

 the recent development of the " Huddersfield " race renders it highly 

 probable that the climatic changes in Britain and Central Europe, due 

 to the advance of civilization and forest clearing, may have been an 

 important factor in evolving the present forms. 



Without seeing the specimens and knowing the locality mentioned 

 by Mons. A. Caradja, it is impossible to say how near they are to Irish 

 specimens, but his reference to them as the " milchweisse form," and 

 his special mention of the fact that " eight of the specimens are of a 

 smoky tint " remind us that one of the Antrim specimens was nearly 

 white. Strange, too, the specimens recorded by Mons. Caradja appear 

 to be entirely restricted to the valleys of the Pruth and Danube or to 

 isolated mountainous valleys, at Tirgu Neamtu, Kloster Neamtu (in 

 Carpathians), Costisa (in the Bistrita valley), Husi (a small town 

 south of Jassy), Jassy, Dorohoi, Comanesti, the whole of Moldavia, 

 Bucovina, Czernowitz, Kadanti, the Bergell (a southern Alpine valley) ; 

 yet he refers to these comparatively low-lying districts as possessing a 

 Continental climate. It would be interesting to get records of the 

 climate and meteorological conditions of the localities where the variety 

 is found, so that we might compare them with our Irish conditions. I 

 am inclined to think, however, that the assumption of the extreme 

 tints both paler (whiter), and darker than the buff-coloured ancestral 



