H. Onslow 



137 



GENEALOGICAL TABLE 

 of B. abietaria. 

 Bred from larvae, Dorking (1915) 



1915 



Bred from larvae, 

 Dorking (1916) 



Bred from pupae, 

 New Forest (1916) 



6 6 9 f f 



i i i 1 9 



9 1916 



'17 4 'ITD 17 B '17 E '13 F 



'ISA, 'ISB, etc. 



'17 C '17fl '17 L 1917 



^ 



1918 



trees, the bark of which they are accustomed to eat until the spring. 

 As soon as the oak was out, they were returned to the cylinders, where 

 they were fed until they pupated, as oak was easier to obtain in large 

 quantities than yew. From the twenty pairings made in 1918, over 

 1600 insects emerged in the following year. 



The melanic form, as will be seen from the following experiments, 

 clearly behaves as a simple Mendelian dominant, no matter how dark 

 the type may be. The result of pairing two melanics, one at least of 

 which was homozygous, was as follows : 



Melanic x Melanic. 

 [DDxDD{DR)\ 



Imagines 



Totals 



479 



