394 GEORG H. M. WAALER 

deepens and at the same time changes into a ruby tone, strikingly 
like the one found in young purple flies. The colour retains its trans- 
parency also in old flies. When.we consider the degree of dilution 
in young brown flies, it seems surprising that the eosin eye colour 
does not show a marked dilution when combined with brown. Like- 
wise brown was tried in combination with the earlier second chromo- 
some eye colour purple, but failed to show a conspicuous dilution in 
double recessive purple brown flies. In fact, these double recessive 
flies cannot be distinguished from pure purple flies. 
The brown flies are of good viability and of normal fertility. 
They may be distinguished with perfect accuracy and ease from wild 
type individuals. 
LITERATURE CITED. 
1. BRIDGES, C. B. 1919. The genetics of purple eye color in Drosophila. Journ. 
of) Exp) Zool) Vol=28, ano. 9. 
2. Bridges, C. B. and MORGAN, T. H. 1919. The second chromosome group of 
mutant characters. Carnegie Inst. Wash. Pub. No. 278. 
TL44 
