H. Onslow 341 



severest. These conditions could not be better fulfilled than in the 

 manufacturing areas, where the woods and vegetation upon which the 

 larvae feed have been largely destroyed and elsewhere contaminated 

 with a chemical deposit. 



E. Goodwin originally found the melanic form of B. consortaria in 

 the same oakwood in North Kent in which he took the black form of 

 T. consonaria. There is a mention of the Kentish form by R. South \ 

 which is referred to var. humperti, Humpert. The second line of the 

 forewings is, however, edged with white, and there is a white sub- 

 marginal line in the English form, but both markings are lacking in 

 var. humperti. All the melanic specimens bred in these experiments 

 had the white lines more or less well developed. E. A. Cockayne reports 

 taking a typical $ at Oxshott in 1914, which had evidently paired with 

 a melanic cT , because the ova deposited produced about equal numbers 

 of both forms. A virgin melanic ? was taken at Oxshott by the same 

 observer in 1919. These melanics he refers to var. consohrinaria Bkh. 

 There are at least two other references to captures at Oxshott, where 

 a large proportion of melanics are said to occur every year, and another 

 specimen was taken at Chislehurst, so that it seems to have soon spread. 

 Mr L. W. Newman tells me that.in 1916 he received a dark $ captured 

 at Oxshott, which in the following year produced a number of specimens, 

 all dark like their parent, and yet considerably lighter than the melanic 

 form. It appears therefore that either the melanic specimens at Oxshott 

 vary considerably, or else an intermediate form must exist. Two of 

 these dark Oxshott insects are shown in Plate XIII, Figs. 3 and 9. 



The original melanic stock which supplied material for these experi- 

 ments was a melanic % from Mr Newman captured at Sutton Coldfield 

 in 1914. This appears to be the first record in Britain of a specimen of 

 the melanic variety being taken outside Surrey. Though all the Surrey 

 specimens may have spread from the original mutant in the Kentish 

 oakwood, it is hardly likely that a specimen could have reached Warwick- 

 shire, unless by the aid of man, so it seems legitimate to suppose that 

 this race must have originated de novo ; this time, be it observed, in the 

 close proximity of Birmingham. The pedigree on the next page gives 

 the parentage of the families dealt with in this paper. 



It will be seen that Mr Newman paired two of the intermediate 

 Oxshott insects with two melanic specimens of the Sutton Coldfield 

 strain, and two of the latter strain were paired to type insects. Three 

 of the resulting families are shown on p. 344 (i.e. '17 ^; 17 5, 171)). 



» South, R., Moths of the British Isles (F. Warne, 1909). 



