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My first specimen of this interesting variety emerged from a 

 pupa I found some years ago in Kilton Woods, near Loftus. It 

 was an intermediate form of striking appearance, the fore wings 

 being black with a few white dots near the outer margin, while 

 the hind wings are beautifully washed with silvery white near 

 the costa, the white part having a narrow black band, which is 

 continued in white on the black part. It is a male, and although 

 I have bred many others since, I have not succeeded in getting 

 anything like it, either by the application of heat or by crossings. 

 Some three years ago I again visited Kilton Woods in company 

 with Mr. T. Ashton Lofthouse, of Middlesbrough, who then took 

 a black crippled female sitting on a tree trunk, which afterwards 

 laid a large quantity of fertile ova, half of which Mr. Lofthouse 

 kindly gave to me. These duly hatched and produced splendid 

 larvffi in all tints of protective colouring, from green to brown, 

 according to the plants I fed them on, and I had thus an oppor- 

 tunity of verifying Mr. Poulton's experiments upon these larvae. 

 They all fed up and pupated in the autumn. The next spring I 

 forced the pupae out by heat slightly before their time, and they 

 gave a good assortment of black and mottled grey imagines, the 

 black, however, preponderating considerably, but, with the excep- 

 tion of one or two, there were no intermediate forms as described 

 above. I allowed the bulk of them to copulate as they emerged, 

 which the black forms did immediately, and I thus conclude 

 that this variety is the most vital. The grey males were the 

 most sluggish, and from their pairings I only obtained very few 

 fertile eggs ; in fact to induce copulation at all I had to put 

 several males to a female, and a great many grey males declined 

 the invitation altogether. It is, however, possible that the fact 

 of their being forced out before their time may have been the 

 cause of this, as the development of the genital apparatus in that 

 case does not appear to keep pace with the rest of the body, 

 although this should have equally applied to the black varieties. 



However, I was fortunate enough to obtain all possible 

 combinations, viz. : — 



Black in copulation with black. 

 Black in copulation with grey. 

 Grey in copulation with black. 

 Grey in copulation with Grey. 



The black females laid the greatest number of ova. All eggs, 

 however, hatched, and I kept all kinds separate with a view to 

 ascertain the result of these crossings, but unfortunately the 

 small number of larvae from the grey varieties, and their 



