MtLANiSM IN YdRKSMlKI-: LEt*lDOrTERA. 319 



In, or had been in and afterwards thrown out, I do not know. But it 

 proves, at any rate, that there was long ago a latent tendency in the species 

 to become mclanic, and that it is quite possible it may oven have been 

 common long before we noticed it.^ 



\ moth which for thirty years of my collecting experience was always 

 regarded as one of our most constant speCies, showing little colour 

 variation, was Odontopera bidtntata, the Yoi-ksIiirB form being of a softj 

 rather pale greyish brown colour. But about ten years ago came the 

 i-eport from "Wakefield tliat a quite black specimen had been taken there, 

 followed during the next several yeats by a few others. Now at Wake- 

 field, and at jNIethley some six miles aAvay, it is quite plentiful, so much 

 so that Mr. George Pal-kin, who resides in the city of Wakefield, told me 

 that last year, in one week, out of the only five specimens which flew into 

 his house, attracted by the light, four were black, and that so rapidly is 

 the form increasing, he thinks that in a few more years tlie pale form will 

 be quite eliminated ! Tliis, too, may be regarded as a sudden rather than 

 a gradual change, for although a few rather darker than ordinary 

 examples do occur, they cannot be regarded as even intermediate forms. 

 In 1904, from a few eggs deposited by a captured black moth, I bred 

 nine specimens, six of which we)-e black and three ordinary. From the 

 black moths in the following year, 1905, I reared a very large brood, 

 about 75 per cent, of which were black ; and from them again this year 

 I bred a considerable number, of which the percentage of black was still 

 greater. Three generations tlius produced an almost entirely black race, 

 which proves that the hereditary tendency towards melanism must be 

 remarkably strong. 



The histoi'y of the melanism of PoUa eld shows a gradual darkening 

 from ahuost white to dark slate colour, and is interesting as occurring in 

 the first Noctua we have yet considered. It is, too, a case of specially 

 local melanism, inasmuch as in my own district, at any rate, although 

 occurring very markedly on the walls all around the town and surround- 

 ing villages of Huddersfield ; on the equally black, or even blacker, walls 

 bordering our high moors, only half a dozen or so miles away, almost all 

 the specimens are of the palest form and can readily be seen from a con- 

 siderable distance. This fact should be noted for our after-discussion. 



Perhaps the most rapid case of change in colour we have yet noticed 

 has been in Larentia multistriijaria. The species has always occurred in 

 abundance in my own district, but up to about 1895 a dark specimen had 

 never been observed in it, although a single black example — and one 

 only — was known to ha\ e emanated from the district. Now nearly forty 

 years ago the late Henry Doubleday wrote to the late James Varley, 

 formerly a prominent lepidopterist in Huddersfield, for eggs of Multi- 

 siriyaria, and I distinctly remember Varley telling me that from the eggs 

 he had sent him Mr. Doubleday had bred a black Midtistrigaria, and the 

 specimen, I believe, is still in the Doubleday Collection at Bethnal Green 

 Museum. Here we have another instance of the latent tendency to 

 melanism, Avhich in this species m as not really developed until over thirty 

 years afterwards. 



In ten years' time the black form has so increased in numbers that 

 Mr. Morley tells us that in some parts of the Skelmanthorpe district the 



' Cf. Porritt, IVans. Ent. Soo. London, 1880, pi, 411, p, xiv., on melanism in Arctia 

 mendica near Huddersfield. 



