392 



THE AMEBIC AN NATURALIST [Vol. XLIX 



of the environment was not fully under control. The 

 conditions under which the experiments were made were, 

 however, favorable for the appearance of the abnormal 

 condition, at least in the first counts of each brood, for 

 the bottles were supplied with an abundance of wet fer- 

 mented food. 



The linkage of abnormal abdomen with white eyes and 

 yellow body color was studied in different combinations ; 

 and since the factor for abnormal abdomen proved to be 

 quite near the other two factors the choice was a favor- 

 able one in certain respects. A special method by means 

 of which the error, due to the variability of the charac- 

 ter, can be largely eliminated will be given after the evi- 

 dence has been presented. 



The Linkage of Abnokmal and White 

 When red-eyed (R) abnormal (Ab) females were mated 

 to white-eyed (W) normal (N) males, red abnormal 

 males and females were produced. 2 When these were 

 mated the results recorded in the next table were ob- 

 tained. 



By means of the following diagram, I have tried to 



show what the expectation is for this combination. The 

 two parallel lines are intended to represent the two sex 

 chromosomes of the Fj female. From her mother she 



2 Throughout this paper I have used the letters E for red eyes, W for 



B for black instead of using the allelomorphic system ; because for present 

 purposes, where analyses are unnecessary, th Mtors suffice most simply 



papers the allelomorphic symbols for the same characters would be: 

 w = the factor for white. W = its normal allelomorph == red. 



A'b = the factor for abn. abd. a'b = its normal allelomorph = normal abd. 

 y = the factor for yellow. Y = its normal allelomorph = gray. 



