186 Some Experiments in Heredity 



grossulariatu (/ GgTt x GgTt ? grossidariata 



Spermatozoa GT, Gt, gT, gt </ GT, ^ Gt, % gT, $ gt eggs. 



F^ Males GGTT = (jrossidariata F., Females GgTT = grossulariata 



2 GGTt = grossulai'iaf a 2 GgTt = grossidariata 



GGtt ="Q" Ggtt ="(}" 



GgTT = grossidariata ggTT = lacticulor 



2 GgTt = grossidariata 2 ggTt = lacticulor 



Ggtt ="Q" ggtt =lacticolor 



The new form ggtt will doubtless be lacticolor, since it lacks the 

 factor G ; it will be a lacticolor carrying the factor for " Q " instead of 

 for the type form. 



As will be seen from mating C the observed results are in fair 

 accord with the hypothesis, and this is also the case with matings D (i) 

 and (ii) and E. 



If this hyjjothesis is con-ect, among the F.2 offspring from the cross 

 " Q" <^ X lacticolor $ there should be " Q " males of type Ggtt and 

 lacticolor females of the types ggTt and ggtt, and that such types may 

 exist is indicated by two pairings made subsequently in 1915, viz. 

 F and G. 



F. About March 10th, 191.5, "Q" </ x grossulariata ? (both 

 parents from family C). This gave only ; 4 grossidariata $ and 4 

 lacticolor $ , besides one extracted dead from the pupa which appeared 

 to be " Q" $ but might possibly have been lacticolor J. 



0. About the same date, grossidariata ^ (from family C or D (i)) 

 X lacticolor $ (from family C or D (ii)) gave only 3 " Q" ? and 3 

 lacticolor $ . 



The interest here lies in the fact that in family F lacticolor $ 

 appears showing the constitution of the " Q " ^ parent to have been 

 Ggtt, for a lacticolor could not be the offspring of a normal " Q" ^ of 

 the type GGtt. Similarly in family G "Q" ^ is produced showing 

 that the lacticolor $ parent was either ggTt or ggtt (and not ggTT — 

 the normal lacticolor constitution). 



A test for the form ggtt would be to mate it with a normal " Q" J' 

 — i.e., one which had not descended through lacticolor — in which case 

 the offspring should all be " Q." 



The fact that only females appear in F and G may be accidental or 

 possibly the lacticolor may have been derived from Dr Doncaster's 



