THE INHERITANCE OF WING-COLOUR IN 

 LEPIDOPTERA. 



VII. MELANISM IN HEMEROPHILA ABRUPTARIA 

 (VAR. FUSGATA, TUTT). 



By H. ONSLOW, 

 Trinity College, Cambridge. 



(With Plate XXV^Iir.) 



The inheritance of the melanic variety of Hemerophila ahruptaria 

 (The Waved Umber) has ah-eady been studied by T. H. Hamling' and 

 E. Harris"^. Their experiments seem to show that the black form is 

 dominant, but the ratio of type to melanic insects, obtained by them in 

 the cross melanic (heterozygous for type) x type, appears to suggest 

 that the inheritance is not that of a simple Mendelian character. For 

 this reason the breeding experiments recorded in the following pages 

 were undertaken, and although they only serve to show that the surmise 

 was mistaken, they are nevertheless perhaps worth recording. 



One point of interest is that the variety fuscata appears to be con- 

 fined to the environs of London, there being but one reference to its capture 

 in the New Forest where it is exceedingly rare. In its distribution this 

 variety is similar to some of the melanic forms already studied, in that it 

 does not originate in any of the manufacturing districts of the North of 

 England. The type insects used in these experiments came from Bexley, 

 Kent (Nos. 1 — 6, PI. XXVIII), and the melanic strain from Holloway, 

 London (Nos. 7 — 12, PL XXVIII). In colour the latter was a deep 

 chocolate brown, though the central band on the fore wings was not always 

 completely obscured. The depth of colour of this band varies considerably, 

 and appears to depend to some extent on the size and vigour of the larvae 

 (see Nos. 11 and 12, PL XXVIII), but there is no difference in colour 

 between a heterozygous melanic carrying type, and a pure homozygous 

 black insect. Of the two sexes the male is usually the darker. 



1 Hamling, T. H., Trans. City of London Ent. Sac. 1905, p. 5. 



■^ Harris, E,, Proc. Ent. Soe. London, 1904, p. Ixxii ; and ibid. 1905, p. Ixiii. 



