HEREDITY OF MELANISM IN LEPIDOPTERA. 

 By W. bo water, B.D.S. 



In certain of the Lepidoptera (not naturally black) black specimens 

 occasionally appear, and it has been noticed that this melanism has 

 become more and more frequent of recent years, that in some species 

 the black specimens are to-day distinctly more numerous than the 

 original type, and in some localities have even superseded it^ 



Such an evolutionary change obviously possesses features of con- 

 siderable scientific interest, and much has been written on the subject 

 of its causation and the exact method in which it is being carried on, 

 but the question is still unsettled. 



Apparently the term melanism as applied to Lepidoptera should be 

 restricted to the substitution or increase of black on the wings or body, 

 or both, at the expense of some other colour ; but any darkening of the 

 ground colour, even if not black, has been included in a general way, 

 although strictly the term melanochroism should be applied to the 

 latter. 



I have compiled a list^ of 211 species of British Lepidoptera in 

 which melanic or melanochroic specimens have been recorded. 



Although the heredity of melanism in the higher orders has been 

 worked out in many species, comparatively little seems to have been 

 done with regard to Lepidoptera, and it is still a fairly open question as 



^ Collective Inquiry as to Progressive Melanism in Lepidoptera. L. Doneaster. Ent. 

 Record, Vol. xviii. 1906. 



2 (a) Melanism and Melanochroism. Tutt. 

 (6) List of varieties and aberrations peculiar to British Isles. Tutt. Ent. Record, 



1902. 

 (c) Melanism in Yorkshire Lepidoptera. Porritt. Tram. Brit. Ass. 1906, 

 {d) Feuille des Jeunes Naturalistes. April, 1913. 

 (e) Standfuss, Handbiich d. Gross-Schmetterlinge, 1896. 

 (/) Les Mecanismes du Melanisme et de V Alhinisme chez les Lepidopteres. Pictet. 



Geneva, 1912. 

 (p) Entomologist and other sources. 



