GENETIC STUDIES ON FLOUR-MOTH 433 



Two pairs of sooty by sooty black produced 46 sooty and 50 

 sooty black, showing that each pair must have been SS.Bb X 

 SS.bb. 



A pair of sooty produced 56 sooty and 21 sooty black, showing 

 that each parent was SS.Bb. 



A sooty black male paired with a black female produced 58 

 black, showing that the pair was SS.bb X ss.bb. The black 

 progeny, sS.bb showed sooty indistinctly as a 'ghost pattern.' 



Two pairs of sooty by sooty produced 29 sooty, 12 type, 

 1 sooty black, and 10 black. Since sooty, type, and black 

 were produced from each mating, the parents must have been 

 Ss.Bb. 



A black male paired with a sooty female produced 6 sooty, 

 7 type, 3 sooty black, and 4 black. Since both type and sooty 

 black were produced the parents must have been sS.bb and Ss.Bb. 

 The theoretical ratio would be 3 sooty (1 SS.Bb and 2 Ss.Bb), 

 1 type (ss.Bb), 1 sooty black (SS.bb), 3 black (2 sS.bb and 1 

 ss.bb). 



A sooty male paired with a type female produced 26 sooty, 

 33 type, and 30 black. Since both type and black were pro- 

 duced, the parents must have been Ss.Bb and ss.Bb. The theo- 

 retical ratio would be 3 sooty (1 Ss.BB and 2 Ss.Bb), 3 type 

 (1 SS.BB and 2 SS.Bb), and 2 black (1 sS.bb and 1 ss.bb). The 

 expected ratio is 33 sooty, 33 type, and 22 black. 



A sooty male paired with a black female produced 32 sooty, 



16 sooty black, and 20 black. Since no type were produced, 

 the male parent must have been homozygous for sooty, and 

 since sooty black were produced, both parents must have carried 

 sooty. The cross was therefore SS.Bb X sS.bb. The theoret- 

 ical ratio would be 2 sooty (SS.Bb and Ss.Bb), 1 sooty black 

 (SS.bb), and 1 black (sS.bb). The expected ratio is 34 sooty, 



17 sooty black, and 17 black, to which the actual numbers al- 

 though small are very close. 



A pair, sooty male by sooty black female, and two pairs, sooty 

 black males by sooty females, produced 66 sooty, 42 sooty black, 

 and 16 black. Since black were produced, the sooty parents 

 were Ss.Bb. The sooty black parents would of course be SS.bb. 



