70 Inheritance of Melanism in Tephrosia (Ectropis) 



TABLE 1. 



Melanic x I'ype (MM x mm). 



Melanics Types 



Percentage 



Family Parentage Males Females Totals Males Females Totals Melanic 



D ^Cx^A* 24 17 41 — — — 100 



E ^Ax^C 25 23 48 — — — 100 



F ^Cx ^B 18 22 40 — — — 100 



G ^£x^C 14 18 32 — — — 100 



Actually reared ... 161 100 



Theoretical result ... 161 100 



* ^ A simply means that the insect in question was chosen from family A or its inbred 

 offspring. 



visible in the Fi broods for certain insects were paler than their melanic 

 parent. Despite this all were undoubted melanics, and none attained, 

 much less overstepped, the range of continuous variation amongst mela- 

 nic insects taken in the woods whence the melanic stocks were secured. 

 These heterozygous melanic insects were paired inter se, back on 

 homozygous melanics derived from a pairing between representatives 

 of the black stocks A and B, and also with imagines bred from a fresh 

 wild female (family H) from Kent. Thus the whole of the pairings 

 possible at this stage and required in our quest were obtained with 

 results set out in tabular form in Tables II and III, 



This result gives us, within the limits of experimental error, the 

 expected 3 : 1 ratio and confirms our views as to the dominance of 

 melanism and the genetical constitution of the individuals in the .^j 

 generation of the cross between pure melanics and pure types. 



Here again the theoretical expectation harmonises with actual fact, 

 for the cross between homozygous •melanics on the one side, and similar 

 heterozygotes on the other, should yield only melanics. 



