DESCRIPTION OF BRISTLE IN D. MELANOGASTER. 



467 



TABLE II. 



P I BRISTLE $ X BLACK PURPLE CURVED c?. 



Bl. Wild Type. 



iQi 225 



B. C, F I BRISTLE $ X BLACK PURPLE CURVED . 



A black purple Bristle curved stock was made up by crossing 

 the black purple Bristle female (which was also heterozygous for 

 curved) from Table II. with a black purple curved male. F x 

 Bristle females from mating of black purple Bristle curved X wild 

 type raised at 31 degrees C. were back-crossed to black purple 

 curved males for six days only with the results shown in Table 

 III. The recombination percentages are as follows: b-p 14.9 

 per cent. ; p-Bl 1.6 per cent. ; Bl-c 23.7 per cent, and p-c 25.3 per 

 cent, which correspond with the values b-p 14.0 per cent, and p-c 

 26.7 per cent, found by Plough ('17) for the same temperature. 



TABLE III. 



P , BLACK PURPLE BRISTLE CURVED $ X WILD TYPE <$ AT 31 C. 

 F Bristle $ X black purple curved c? 6 days only. 



That Bristle is lethal when homozygous was indicated when 

 Bristle males and females (from Table I.) were inbred. Such 

 matings gave approximately 2/3 Bristle and 1/3 wild type off- 

 spring (Table IV.). Further demonstration was obtained as 

 follows: A black Bristle curved male (from Table II.) was mated 

 to a wild type female and F 1 males and females were inbred. 

 The eight curved and one black offspring out of 145 represent 



