No. 575] 



.LV APTEROUS DBOsOnilLA 



683 



9:3:3:1. These results clearly show the independence 

 (i. e., lack of linkage) of apterous and pink. 



Table V includes all matings (giving apterous) in Ex- 

 periment III, for the purpose of showing the ratio of 

 winged to apterous. 



TABLE V 



Experiment IV.— To determine the relation between 

 apterous and characters in Group II. 



The mutant called "black" (having black body and 

 wings) was used in this experiment as a representative of 

 Group II. No direct matings with apterous individuals, 

 such as obtained in the three preceding cases, could be 

 effected here, and consequently the winged brothers and 

 sisters of apterous had to be used for crossing with black, 

 according to the method described in the introduction. 

 Matings of tins kind (in pairs) gave, in F„ winged Hies, 

 some of which were heterozygous for apterous and black. 

 These inbred (also in pairs) gave winged and apterous, 

 and gray and black, as shown below: 

 P, Black J homozygous for wings A P b-A P b, 

 Gray $ heterozygous for apterous A P B-a P B. 



