H. Onslow 241 



poculiarly pale, wheriMva inoHt of tho ^f if hiul an appreciable <|uaiitity 

 of yellow. In family *1H V, for inHtance, then* wen* Wl J % iuxl 20 ^f J , 

 their ru8pectivo coloun* being iih followH: 



Average cx)lour of % J wjw [11: 1 Oj 



Avenige colour of ^^^^^ was [1*7 : \'h\ 

 5 % % wen^ <leej)cr than [1-2:1 :i] 



lOc/c/" L2<>.-J<iJ. 



Similarly, in the small family '18 III, there were ^ %% aFid « c/</» <h«' 

 respective colours being jus follows : 



Average colour of J ? wjus [11 : li] 

 c/'c/' was [21:1 •!)]. 



It was at first thought that there was some j)eculiarity in lacticolor 

 which inhibits the development of the j)ale yellow colour cli.ir;u't<'risin;4 

 the heU^rozygous form oi grossulanata. This seemed the innrc pn>l)al)l<! 

 becjiuse one of Dr Doncaster's brood, already recorded, namely, family 



'08-5 lactkolvr ? [10: 10] x Uicticolor f [40:30] (see Fig. 1.')), 



contained, in spite of the deep colour of the cT parent, 11 c/c/* '^"'' 

 14- J J only two of which were deejxT than [12 : V\\ The remainder 

 had an average colour-value of [I'O : 10], there being practically no 

 diflference in the colour of the ^ ^ and the % % . 



In family *18 V, the % parent was lacticolor and consequently both 

 ffff and J J were heterozygous grossulariata. A comparison between 

 these % ? and the lacticolor J ? of the reciprocal cross shows that it is 

 femaleness, or some factor associated with it, rather than lacticolor that 

 prevents the development of the pigment in the pale yellow^ /",$?. 

 This can be seen from the fact that the grossulariata J J were even 

 paler than the lacticolor J J from the reciprocal pairing, whereas the </(/ 

 in the two families were approximately the same depth of yellow. 



In family '18 V there were 23 $ $ and 23 (f^ the colours of which 

 were as follows : 



Average colour of $ $ was [10: 10] 

 Average colour of (/J* was [1*4 : 16]. 



It was previously suggested on p. 219 that there was "a slight tendency 

 for the J J to be paler than the cTcT' ' ^^^^ this difference was not iiion- 

 than 8 — 9 ^/, in the heterozygous J J either of the I\ <>r F. generation. 

 Although this point has not been tested (except in faniily 'Ob')) by 

 Journ. of Gen. viii 17 



