64 Inheritance of Melanism in Tephrosia (Ectropis) 



Fig. 2. Genitalia of T. bistortata. 

 A = Male valvae, etc. ; B^^Edceagus; C-=Signum of female bursa oopulatrix. 



^ 



C B 



Fig. 3. Heads of cristae hairs. 

 C = Cup-shaped heads of those of T. crepuscularia ; 

 B ■= Disc-shaped heads of those of T. bistortata. 



What is still more important, although the forms are reciprocally 

 fertile, when the two possible crosses are made the compositions of the 

 resulting broods are not alike. When T. bistortata provides the male 

 the sexes appear in their usual proportions, but when T. crepuscularia 

 supplies that sex the broods are unisexual and male under ordinary 



