H. Onslow 



345 



five cases the type parents come from 1917 pairings of melanic x type, 

 which are indicated in brackets, and in all other cases they come from 

 wild pupae. The expected ratio of half and half is seen to be approached 

 very closely, and there is probably little doubt that the previous table 

 would not have shown such a wide divergence, had the numbers been as 

 considerable. The last family in the table, '18 L, the numbers of which 

 have been printed in italics, produced, not melanics and types, but 

 melanics and intermediates (sec Plate XIII, Figs. 4 and 10) in equal 

 numbers. As has been said, this dark form, though slightly darker than 

 the Oxshott strain, was probably introduced by it, since the melanic % 

 parent came from (Oxshott) ? x (Sutton Coldfield) ^ . A number of 

 further matings l;iave, however, been carried out with this form, and the 

 results, if they prove of any interest, will be published in due course. 



Attention should perhaps be called to the curious inverse relation- 

 ship between sex and colour in some of the above matings, there being 

 an excess of one sex in the melanic offspring, and au excess of the other 

 sex in the type offspring. This occurs in families 1914, '17 J., 'VJ B, 

 '17 E, '18 D and '18 M, there being as a rule an excess of melanic % $ and 

 of type (/'</' when the % parent is a type, and an excess of melanic j/'</ 

 and type % $ when the % parent is melanic. It is quite probable that 

 this relationship may be fortuitous, as it does not occur in nearly all the 

 families. Nevertheless, '17 A, '17 B, and '17 E are all descended from 

 the same strain of melanic parents, and in both the families 'IS M and 

 '18 D, the melanic parent comes from '17 E. 



A small number of type insects were also paired together, and as was 

 expected, they all gave nothing but types. 



Type X Type. 

 RR X RR. 



Imagines 



Melanic 



Type 



Family Bred by Female x Male 



'17 r Ova from Type x (J ? 



L, Newman (Bexley) 



'18^ H. 0. Type x Type 



(ex '17^) (ex'lTC) 



'18 Q H. O. Type x Type 



(ex '17 D) (New Forest) 



'18^ H. O. Type x Type 



(ex'17£) (ex'17D) 



Male Female Totals Male Female Totals 

 — — — 8 6 14 



— 62 



— 45 



— 43 



43 105 

 28 68 

 45 88 



Totals 



275 



