:X PREFACE. 



Perhaps no subject in connection with Lepidoptera has 

 proved of greater interest to Yorkshire lepidopterists, and 

 especially to those of the Western division, than Melanism. 

 Towards twenty years ago, it began to be noticed that 

 various species of which a black or nearly black specimen 

 bad occasionally been taken, were producing- these dark 

 forms in increasing numbers, several of them rather rapidly. 

 Long before then, indeed, a perfectly black form of Aniphy- 

 dasis hetidaria was well known, but at that time was so 

 comparatively seldom taken as to be regarded as a rarity. 

 Now it has not only become the dominant form, but in 

 probably most of the South West Riding area has practically 

 altogether ousted the original pale ordinary form. In the 

 Huddersfield district, I have only seen one pale specimen 

 during the past eight or nine years, and a typical specimen 

 is quite a rarity now compared with what the black form 

 was even in the time of my collecting experience. Other 

 species which are going rapidly in the same direction are, 

 Phigalia pilosaria, Boarmia repandata, Tephrosia biundularia, 

 Hybernia progemmaria, Oporabia dilutata, Larentia multi- 

 strigaria, Thera variata, Ac7'onycta ru?ntcis, Polia chi, 

 Hydrocampa nyniphcealis, and Diurnea fagella, and in some 

 of these indeed in the South Western division, the black 

 specimens seem already to preponderate. Besides these 

 there are several species which, although comparatively pale 

 in most counties in Britain, have been darker in Yorkshire, 

 so far as we know, ever since any interest was taken in 

 lepidoptera. Among them may be mentioned Boarmia 

 rho77iboidaria, Scodlona belgiaria, Melanippe tristata, Cida^'ia 

 testata, Notodonta canielina, Notodonta di'omedarius, Notodonta 

 dodoncea, Acronycta leporina, Apaniea oculea (in the South 

 West), Minna strigilis, Eptuida viniinalis, etc., and whether 

 they too were originally pale with us, we are now unable 

 to determine. The species in our county in which Melanism 

 has become so strongly developed that in various districts 



Trans. Y.N.U. Series D, Vol. 2. Dec. 1903. 



