38 



THE ORIGIN OF GYNANDROMORPHS. 



one of the maternal lethal-bearing X's occurred with the production of 

 bifid tan male parts. 



No. 1818. July 4, 1915. C. B. Bridges. Text-figure 18 (diagram). 



Parentage. One X chromosome of the mother carried the genes for sable 

 and for forked; the other was wild-type. The X chromosome of the father 

 carried the gene for forked. 



Description. The gynandromorph was completely bilateral, the left side 

 being male and the right female. The fly was not forked on either side. 

 The genitalia were female. Sections showed ovaries on both sides. 



V 



TEXT-FIGURE 17. 



TEXT-FIGURE 18. 



TEXT-FIGURE 19. 



Explanation. An egg containing the normal X chromosome was fertilized 

 by the forked sperm. A paternal X suffered elimination, leaving a normal 

 X to produce the male side. The female side was also normal, because the 

 maternal X present carried the normal allelomorph of forked. 



No. T. July, 1915. E. M. Wallace. Text-figure 19 (diagram). 



Parentage. The parentage is unrecorded, but from the characters shown 

 by the gynandromorph it is probable that the fly came from notch stock. 

 The mother carried the dominant gene for notch wing in one X and the gene 

 for eosin in the other. The father was eosin. 



Description. The right side was male with a sex-comb, a short wild-type 

 wing, smaller bristles, smaller half-thorax and half-abdomen. The tip of 



