206 GENETICS IN RELATION TO AGRICULTURE 
linked character. As it occurs in the wild, the currant. moth is usually 
of the typical form which is characterized by dark markings on the wings 
which although highly variable are of characteristic shape and arranged 
ina definite pattern. This is the form styled grossulariata. Occasionally 
in nature, however, a female is discovered which is much lighter than 
Fie. 93.—Diagram illustrating the inheritance of lacticolor type in Abraxas. <A lacticolor 
female mated to a grossulariata male. (Adapted from Morgan.) 
the type on account of a reduction both in number and size of the black 
markings of the wings. This is the form styled lacticolor. It is of in- 
terest to note that according to Doncaster, save in one doubtful case, 
only females of the lact?color type have been discovered in nature. 
The inheritance of lacticolor type is illustrated diagrammatically in 
Figs. 93 and 94. In these diagrams the W-chromosome is represented 
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