H. Onslow 343 



with the types. The type specimens Figs. 1, 2, 7 and 8 all vary 

 appreciably. The females are certainly greyer than the males, many of 

 which have a pale buff line giving the whole insect a slightly yellow 

 appearance. The darkest type specimen bred is shown in Fig. 8. There 

 were only a few insects as dark as this, but there is always the possibility 

 that they may have been specimens of the dark intermediate form. 

 A number of pairings were carried out with the 1917 families, crosses 

 being made with the melanic strain and a race of type insects from 

 pupae collected in the New Forest. The average appearance of these 

 insects, one of which is illustrated in Fig. 2, is much the same as that of 

 the types extracted from the melanics, a typical specimen of which is 

 shown in Fig. 7. The melanics were all of a deep grey with a white sub- 

 marginal line, as shown in Figs. 5, 6, 11 and 12. There was' some 

 variation, certain insects being even paler than Fig. 11, but they were 

 all without exception quite distinct from both type and intermediate 

 specimens, chiefly owing to the lack of any pattern, even in the palest 

 insects. This difference, though very distinct soon after emergence, 

 when all records were made, gets much fainter after the insects have 

 been dried some months. 



The larvae proved very hardy, especially the melanic race. They were 

 fed entirely with oak, upon the hard, older leaves of which they thrived 

 remarkably well. They were kept in the usual glass breeding cylinders, 

 and in the spring of 1919 over a thousand insects emerged. 



The result of mating together melanics, both of which were evidently 

 heterozygous, was as follows : 



Melanic x Melanic. 

 DR X DR. 



Imagines 



. ^ 



Mel&nic Type 



Family Male Female Totals Male Female Totals 



'18 G 19 15 34 12 10 22 



'18 if 3 12 15 3 5 8 



'181 10 11 21 2 2 4 



'IBJ 23 27 60 13 8 21 



Totals ... 120(69%) 55(31%) 



Expectation 131-25 43-75 



Unfortunately, no matings could be made with homozygous melanics^ 



1 Through the courtesy of Prof. J. W. H. Harrison, who has bred this species 

 extensively, I am enabled to say that in 14 broods of melanic by melanic, he obtained 

 662 melanic $ $ and 653 melanic ^ ^ , but no types. 



