LIFE CYCLE OF HYDATINA SENTA 165 



When a member of one of the above pure hnes was mated with a 

 member of the other pure Hne, the zygotes gave rise to pure hnes 

 having in every case a higher proportion of male-producers than 

 had either parent pure hne. This was true of every zygote tested, 

 regardless of which pure line had furnished the female parent. 



When a member of one of the pure lines derived from the crosses 

 above was mated with a member of one of the original parent lines, 

 the zygote gave rise to a pure line having a proportion of male- 

 producers intermediate between those of the two parent lines of 

 this zygote. 



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