Table XVILI. 
Drosophila Melanogaster. 
311 
F, generation from curved 2 by black, purple curved ©. 
Gray Black Black Gray 
Number red purple red purple 
curved curved curved curved 
1 128 35 6 6 
la 180 35 10 U 
2 199 45 10 8 
2a 116 32 5 2 
3 123 30 7 8 
3a 119 32 1 2 
4 165 43 2 5 
4a 44 14 1 3 
POtal. vi: 1074 276 49 42 
4. Black purple curved 92 by curved <. 
The F, from the reciprocal cross to that in 
curved sons and 231 gray red eyed curved daughters. 
F,, the different classes in table XIX. 
| 
3 gave 
202 gray red eyed 
These inbred gave in 
Table XIX. F, generation from black, purple, curved 9 by curved <a. 
Number 
Gray Black 
red purple 
eurved curved 
248 52 
273 59 
313 a 
263 59 
1097 247 
Blaek 
red 
eurved 
Gray 
purple 
curved 
25 
11 
7 
6 
49 
The fact that all the flies in the F, and F, are curved shows that the two 
mutants are identical. 
The last two tables give data on the linkage of pur- 
ple and black. There are 184 cross overs in a total of 2878 a linkage of 12.8. 
5. The Black, purple vestigial was crossed to a new wild stock from 
Arlington, Md. Over 500 sons and daughters were like the wild type. 
Since 
crossing over does not take place in the males, F, females whose composition 
was (bp v BP V) were back crossed to black purple vestigial (b p v).. The 
