FERTILITY AND STERILITY IN DROSOPHILA 



149 



stock were chosen to cross into the Woods Hole stock (see table 

 4, Nos. 149, 151, and 172). The pairs that were tested from these 

 different families as a control show the sterility to have been 

 present in different intensities in these families; No. 149; 11 pairs 

 in 26 were sterile; No. 151, 5 pairs in 21 were sterile; No. 172, 12 

 pairs in 28 were sterile. That the controls give a fair measure of 

 the sterility is shown by the crosses made into the fertile Woods 

 Hole stock. These crosses are given, together with the sterility 

 as it appeared in the Fi and F2 generations, in table 13 a to 13 f. 



In these tables the first nmnber gives the serial number of the 

 cross (e.g., inbred male by Woods Hole female) and is designated 

 as Pi. The second column gives the number of pairs of offspring 

 that were tested from the given family, for the Fi generation, while 

 the next column gives the corresponding number that were sterile. 

 The fourth column indicates the number of pairs selected to be- 

 come the parents of the F2 generation. The succeeding columns 

 give the corresponding number of pairs tested and sterility as it 

 affected the different sexes. 



Crosses between inbred d^ and Woods Hole 9 



TABLE 13 a 



Crosses between the inbred stock and the Woods Hole stock showing the behavior of the 

 sterility in the Fi and Fi generations. Inbred cf No. 149 X Woods Hole 9 



THE JOURNAL O* EXPERIMENTAL ZOOLOGY, VOL. 17, NO. 1 



