146 W. J. MOENKHAUS 
pair from which a fairly large number of offspring has been 
obtained shows a high female ratio for instance, this may be 
taken as a pretty safe indication that the female ratio would be 
high if all or a much larger number had been obtained. 
For the next generation ten pairs were taken from brood 9 with 
aratio of 1.1.94. Brood 3, with a ratio of 1:2.31, would have been 
a more favorable one to select from, but this is not always possible 
since the matings must be made before all the offsprmg have 
emerged and therefore all the data for the complete ratio is ob- 
tained. Only four pairs of this series of matings came through 
safely, due purely to the lack of time to give them the attention _ 
they should have had. The four pairs threw the following sex- 
ratios: 1: 2.33; 1:2,29; 1:1.27; 11.81. The ratio for the entire 
brood was 1:1.82 (215 2: 391 ¢). This ratio was somewhat more 
predominantly female. 
Pairs were now selected from the brood 8 with a ratio of 1:2.29. 
Of the seven pairs mated the offspring of only four was obtained 
and the number of young in each case was quite small. The 
ratio for all the offspring of the generation was 1:2.17 (93 @ to 
201 ¢). The total number here involved is so small that not 
too much importance should be attached to the increased female 
ratio. 
For the matings of the next generation there is little doubt 
that an unfortunate selection was made. The brood from which 
the matings were taken showed a ratio of 1:2.46 but this ratio was 
based on numbers so small (52) that it probably did not represent 
the true ratio of the pair. This may account for the drop in the 
ratio for all the broods of the 4th generation to 1:1.386 (854 4 
483 9). 
Two sets of matings were now made from as many broods of the 
fourth generation. One of these series was again taken from the 
brood showing the most favorable female ratio 1:1.90 (85 2 
162 ¢), but the other series was taken from a brood showing a 
relatively low female ratio, 1:1.04 (64 # 67 ¢). From the 
former the ratio of five pairs was obtained showing a ratio of 1:1.39 
(372 2z—5d18 ¢) and from the latter the ratio of 7 pairs, show- 
ing a ratio of 1:1.07 (496 ~: 535 ¢). 
