Hepialus hectus (the female), 

 Arctia fuliginosa, 

 Arctia mendica, 

 Arctia lubricipeda, 

 Bombyx quercus (var. calluna?), 

 Ennomos fuscantaria, 

 Fidonia atomaria, 

 Abraxas ulmata, 

 Hybernia aurantiaria, 

 Hybernia defoliaria, 

 Eubolia palumbaria, 

 Cymatophora diluta, 

 Xylophasia rurea, 

 Ag-rotis segetum, 

 Ag-rotis tritici, 

 Polia flavocincta, 

 Agriopis aprilina, 

 Aplecta nebulosa, 

 Hadena dentina, 

 Cloantha solidaginis, 

 Scoparia cembrse, 

 and probably many of the micro-lepidoptera. 



As has already been stated this melanism is in Yorkshire 

 far more prevalent in the South West than in other parts, 

 and except in similar districts in Lancashire occurs but little 

 anywhere else in Britain. Many theories have been ad- 

 vanced to account for it, but none of which seem to be 

 thoroughly satisfactory. As, however, it has been clearly 

 shown that melanism prevails far more in the manufacturing- 

 districts of Lancashire and Yorkshire, and consequently 

 where the atmosphere is largely polluted with smoke, than 

 elsewhere, my own inclination leans to the theory that this 

 smoke, along with damp, is the most probable cause. The 

 trees, walls, moorlands, etc., in these districts become so 



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



