INBREEDING AND SELECTION IN DROSOPHILA AMPELOPHILA 133 
agents and that the latter have not suffered in this regard as a 
result of inbreeding. 
In order to determine the total number of eggs produced it was 
necessary to isolate the pairs and twice each day pick off all the 
eggs that had been deposited in and around the food provided. 
This proved to bea most laborious process, for the eggs are too small 
to be followed safely with the naked eye and had to be removed 
individually with the point of a needle. Too much value must not 
be attached to this measure for the reason that the rate and, 
therefore, probably the number of eggs deposited seems to depend 
somewhat, at least, on the condition of the food present, and for the 
TABLE 2 
Strain 6 
Number of generations inbred............. aac 3 5 6 | 3) s, 
Number of days eggs were counted........ 27] 30 34) | odes 32 
Total number of eggs laid.............. 433 | 617 | 480 | 724 | 455 | 516 
Strain 7 
a fs er i. : Lae 
| | 
Number of generations inbred ............| 2 | 3 | 5 | 6 | 9; 10 
Number of days eggs were counted........ 26 33 29 | 23 | 33 28 
Total number of eggs laid.............. 654 | 662| 539] 498| 907) 429 
reason that only the eggs deposited during the first twenty-five or 
thirty days were counted. These creatures live to ke very much 
older. We have kept females alive 153 days, but after the first 
twenty-five or thirty days the eggs come only in small numbers. 
Table 2 gives the actual counts of several females of both strains 
6 and 7. 
We see from the above counts that no material reduction has 
occurred in egg production during nine and ten generations of 
inbreeding. Such variations as occur may, of course, represent 
individual differences in the females. 
The data given in table 1 of the relative hatching and emerging 
qualities of the young of normals and of pairs inbred for seventeen 
generations shows that there is no difference in this respect. 
