630 
GENETICS: A. WEI N STEIN 
Proc. N. a. S. 
the complementary classes are so nearly equal. Moreover, if there was 
overlapping between vesiculated and normal, we should expect some 
genetically yellow vesiculated flies to appear merely yellow (thus simulat- 
ing double crossovers); but no merely yellow flies were observed in this 
cross. Whatever error there may be does not influence the determination 
of the yellow crossveinless distance; furthermore, the order of the factors 
is not obscured. 
Linkage of Crossveinless with Magenta and Forked. — Crosses of cross- 
veinless with magenta and forked indicate that the crossveinless magenta 
distance is 36.0 and the magenta forked distance 2.7 units. This would 
place forked 38.7 units from crossveinless and 56.3 units from yellow. 
However, the crossveinless magenta distance is so long that double crossing 
over occurs within it (see tables 3B and 4C) ; and the discovery of other 
mutations within this region will probably move magenta and forked 
farther to the right. If the ratio of the crossveinless forked distances in 
D. virilis and D. melanogaster is the same as that of the yellow cross- 
veinless regions (17.6 to 13.7), forked in D. virilis should be about 54 
units from crossveinless and about 71 uaits from yellow. 
The Locus of Hairy. — Crosses involving crossveinless and hairy (table 3) 
indicate that the two loci are about 31 units apart. 
TABLE 3 
A. vSoNS OF Females 
h 
CUI^TURE NO. 
0 
] 
2 
1,2 
y cv 
h 
y h 
cv 
y cv h 
+ 
y 
cv h 
1563 
15 
13 
3 
2 
6 
9 
1 
1564 
6 
3 
4 
1 
1567 
5 
7 
1 
2 
4 
Totals. . . 
26 
23 
4 
4 
6 
17 
1 
1 
y cv h m ^ 
B. Sons op . Females 
CUI.TURE NO. 
0 
1 
2 
3 
1,2 
1,3 
2,3 
y cv h m 
+ 
y 
cv hm 
3 
2 
y cv 
h m 
y cv h 
m 
y h m 
cv 
1 
5 
y m 
cv h 
y cv m 
h 
1422 
1424 
15 
19 
15 
37 
5 
5 
11 
17 
4 
8 
5 
1 
2 
1 
1 
1 
1 
1 
Totals 
34 
52 
10 
5 
28 
12 
5 
1 
2 
6 
1 
2 
1 
1 
