INHERITANCE OF WING COLOUR IN 

 LEPIDOPTERA. 



II. MELANISM IN TEPHR08IA CON SON ARIA 

 (VAR. NIGRA BANKES). 



By H. ONSLOW. 

 (With Plate 11.) 



In a previous communication^ the writer described a case of variation 

 in Abraxas grossulariata, involving a change in the pigment of the 

 normal ground-colour, from white to yellow. The present note deals 

 with an example of melanism, one of the most remarkable phenomena 

 of variation, because of its recent rapid progress in England and on the 

 Continent. In an article by Bowater^ evidence is given, showing that 

 the melanic variety of Odontoptera bidentata, though somewhat variable 

 in intensity, is dominant to the ordinary pale form. The same author 

 summarises most of the available breeding experiments carried out with 

 other melanic varieties. Though the published evidence is scanty and 

 often obscure, he concludes that melanism may sometimes be recessive, 

 but that it is more frequently dominant to the type form. 



Melanism is widely distributed among the Geometridae, and is espe- 

 cially frequent in the sub-family Boarmiinae, a great number of which 

 have melanic forms. Among other species the following are at present 

 being investigated, and the results will shortly be published : Boarmia 

 abietaria, Boarmia consortaria, and Tephrosia consonaria. The last- 

 mentioned species forms the subject of the present communication. 



The experiments were planned so that the inheritance of melanism 

 might be studied on a much larger scale than is possible by compiling 

 the published accounts of chance experiments. The primary object, 

 however, was to select two species, preferably closely related, in one of 



1 Onslow, H., Journal of Genetics, Vol. viii. No. 4, p. 209, Sept. 1919. 

 * Bowater, W., Journal of Genetics, Vol. iii. p. 299, April 1914. 



