304 Proceedings of Indiana Academy of Science. 
2. Spineless 2 by curved o’. 
The reciprocal cross in which the spineless ? is paired to the curved 
is given in table IV. All the F, were like the wild type. 
Table IV. FF, generation from spineless 9 by curved <. 
Number Normal Normal 
of Wild wing spines Curved 
Mating type spineless curved spineless 
1 G2 31 Pip 10 
2 82 23 22 2 
3 79 3 26 0 
4 70 22 18 8 
5 50 17 | 18 7 
6 79 23 | 19 6 
a 72 8 20 0 
8 73 ily 27 1 
9 83 19 16 2 
10 | 1 17 28 S 
11 | 76 29 27 11 
12 | ie 15 15 5 
13 82 8 23 1 
14 75 1S 24 2 
15 | 61 16 21 8 
16 72 22 24 11 
zy 13 1 a 1 
18 | 21 7 7 5 
19 68 37 8 6 
20 SO | 15) 11 4 
21 78 21 25 7 
22 42 20 17 1 
Ze 20 3 10 2 
24 | 62 15 Le 10 
AN Gtalenees - 1546 404 457 1s 
Tables III] and IV give evidence of free Mendelian assortment of curyed 
and spineless since the classes approximate a ratio of 9:3:3:1. We con- 
clude that the gene for curyed is borne by a chromosome other than IIT. 
3. Deficiency of the double recessive curved spineless in crowded conditions. 
These combinations have been made many times with the same result 
except that when the cultures are crowded there is a marked suppression of 
the double recessive. Table V gives an F, count from crowded conditions. 
It is to be noted that only approximately half the number of double reces- 
sives appear under unfavorable conditions. 
