34 



T. H. MOEGAN 



and since the former characters are associated at times with 

 diminishing returns, I give in the next table some results where 

 only black and gray color are involved: 



G 9 by B cT 



G 9 

 G c^ 



[Gray 9 



J Gray d" ■ 



] Black 9 . 



(Black d'. 



.867 

 .811 

 .201 

 .180 



There are 1678 grays and 381 blacks. The ratio is approxi- 

 mately four to one which is not very different from the pre- 

 ceding ratio. The analysis of this cross is as follows: 



Gray 9 BYBrX — BYBrX 

 Black cf ByBrX — byBr 



Fi 



Gray 9 BYfirX — ByBrX 

 Gray d BYBrX — byBr 



Gametes of Fi 



BYBrX — ByBr A 



BYBrX — ByBrX — byBr — bYBr 



Gray 9 3 

 Gray cf 3 



Black 9 1 

 Black d 1 



The reciprocal cross, gray male by black female gave the 

 following results: 



B 9 by G c? 



Gray 9 

 Gray d 



Gray 9 



Gray cf 



Black 9 



Black d 



,1465 



1453 



344 



299 



The expectation is here also three grays to one black. The 

 total for the grays is 2918, and for the blacks 643, which is about 

 4^ to 1. In the grays, the mal^s and femalfes are nearly equal, 

 while in the blacks, the females exceed the males by a fair mar- 

 gin. Since these numbers also are derived from mixed counts 

 (as before) I give below a count involving only the two colors 

 in question : 



B 9 by G c? = 



Gray 9 

 Gray c? 



Gray 9 836 



Gray d 875 



Black 9 209 



.Black d 148 



