THE ORIGIN OF GYNANDROMORPHS. 7 



red chromosome, and show the corresponding characters, which in fact 

 it does. If the other chromosome had lost one of its halves at the 

 critical division, the male side should be yellow white, which is not the 

 case. Evidently, then, it must have been a yellow white daughter 

 chromosome that was lost in this case. In regard to the five autosomal 

 characters, it is clear that since both male and female sides show all the 

 dominant characters, both sides of the body received the autosome that 

 bears their genes. This hypothesis thus covers the facts in the case. 

 Sections of the abdomen showed abnormal gonads that appeared to 

 be testes. 



Another gynandromorph is drawn in plate 1, figure 2. It, too, 

 came from this same cross of a yellow white male by a female of a 

 race with the same five recessive characters. It is not a bilateral 



TEXT-FIGURE 2. 



gynandromorph, but more nearly an anterior-posterior combination. 

 The abdomen is male, and since the forelegs bear no sex-combs, some 

 at least of the anterior end is female. One wing is male; at least it 

 is shorter than the one on the opposite side, which is presumably 

 female. As in the last case, the fly shows only the characteristics 

 belonging to the normal allelomorphs of the five recessive autosomal 

 factors. The analysis here is the same as above. 



Another gynandromorph, drawn in text-figure 2, arose from a cross 

 between a male that was heterozygous for the two dominant autosomal 

 genes for star eyes and for dichaete bristles and a female that was notch 



