328 WINGE, THE INTERACTION BETWEEN TWO CLOSELY LINKED LETHALS 








Spread Normal 
22 dd 22 dd 
K 27 62 55 31 38 
K 34 33 30 16 15 
K 41 52 71121231 33 
K 43 58 68 30 30 
K 49 83 64 46 43 
K 50 43 44 24 22 
K 54 67 68 35 45 
K 63 66 54 29 34 
K 79 67 71 31 38 
~ K 81 86 59 43 31 
K 91 48 55 35 24 
K 92 11 2 see : 
K 93 55 48 28 29 
K 99 41 49 26 22 
K 103 64 70 43 33 
836 808 451 434 
Found in all. . . 1644 885 
Theoretically . . . 1686 843 


unexpected result. I do not quite realize how to explain this, but 
so much is certain that this segregation cannot as a matter of 
course be added to the others. It is evident that it is not the 
numerical relation 2:1, but 1:1 which is found here, and I find 
the explanation most probable that one of the two paired supposed 
New Spread individuals only apparently has been Spread, as it 
may be possible to mistake the type, when the flies are so young 
that their wings are not fully expanded. When the parent individuals 
on the 11th day after the mating were removed, it must then have 
escaped the attention that one individual was normal-winged. The 
said ‘wo individuals used for culture 56 were taken out of a culture, 
in which were New normal and New Spread individuals, viz. F, 
of Old Spread x Old normal. In case a New normal individual 
is used instead of aSpread through a mistake, the numerical relation 



