628 
GENETICS: A. WEINSTEIN 
Proc. N. a. S. 
of vesiculated by vesiculated sometimes produce apparently normal 
flies which, however, behave genetically like vesiculated. Thus an 
apparently normal female from vesiculated stock mated by a vesiculated 
male produced 35 vesiculated and 3 normal females, and 48 vesiculated 
and 1 normal male. It is, therefore, possible that in the present experi- 
ment some non-crossover vesiculated flies appeared normal winged and 
were classed as crossovers between cross veinless and vesiculated. Simi- 
larly, some flies that were genetically yellow cross veinless vesiculated may 
TABLE 1 
^ y (^"v ^ 
Offspring of Females 
vs 
cuIvTure no. 
FEMALES 
MALES 
0 
1 
2 
y cv 
vs 
y vs 
cv 
y cv vs 
+ 
Totals 
1591 
62 
36 
29 
4 
4 
1 
3 
77 
1592 
90 
40 
38 
9 
13 
1 
101 
1593 
69 
24 
29 
5 
5 
1 
64 
1703 
121 
37 
35 
12 
7 
1 
92 
1704 
113 
59 
40 
9 
14 
1 
123 
1705 
106 
42 
34 
10 
14 
1 
101 
1706 
120 
42 
43 
11 
9 
1 
1 
107 
1707 
116 
45 
46 
8 
11 
1 
111 
1708 
52 
24 
21 
2 
1 
48 
1709 
84 
19 
31 
8 
6 
2 
66 
1710 
88 
34 
43 
7 
6 
90 
1711 
93 
22 
43 
12 
5 
82 
1712 
91 
38 
32 
11 
14 
1 
96 
1713 
65 
24 
23 
5 
12 
1 
65 
1714 
59 
12 
18 
8 
1 
39 
1715 
76 
40 
29 
9 
5 
1 
84 
1716 
88 
32 
23 
7 
6 
68 
1717 
74 
20 
31 
4 
7 
62 
1718 
91 
31 
33 
7 
12 
1 
84 
Totals 
1658 
621 
621 
148 
152 
8 
10 
1560 
have appeared and been classed as yellow cross veinless. This second 
error would tend to counterbalance the first, but only slightly, because 
the much larger size of the non-crossover class would make the number 
of vesiculated flies simulating normal much greater than the number of 
yellow cross veinless vesiculated flies simulating yellow cross veinless. 
Consequently, the cross veinless vesiculated distance, if in error, should 
be shorter than the calculated value. It seems, however, unlikely that 
in this experiment any large error was introduced in this way, because 
