134 Messrs. Prout and Bacot. On Cross-breeding of [Jan. 8, 



the total, therefore, 45 typical and 100 melanic. Thus the segregation was 

 Mendelian in its completeness, but less so in its proportions. 



Cluny. — A little later, A. Bacot followed up this experiment with another 

 on the same species, this time with material from Cluny, Aberdeenshire. 

 The results are recorded and discussed in the ' Proceedings of the Entomo- 

 logical Society of London' for 1905, pp. lxvii-lxxi * and more briefly in 1 The 

 Entomologist's Eecord,' vol. 17, pp. 340-341. In the generation F 1 60 per 

 cent, of non-melanic against 40 per cent, of melanic were reared from 

 melanic g x non-melanic $ . In F 2 100 per cent, non-melanic appeared 

 from non-melanic parents, the melanic $ grandparents showing no influence ; 

 on the other hand, from extracted melanic pairings of like parentage, F 2 

 consisted of : in two broods, 30 per cent, non-melanic to 70 per cent, melanic ; 

 in another brood, 21 per cent, non-melanic to 79 per cent, melanic. In F 3 , 

 so far as tested, both forms bred true, i.e., two pairings of non-melanic x non- 

 melanic produced non-melanic offspring only (6 and 22 specimens 

 respectively), and two pairings of melanic gave melanic only (24 and 

 12 specimens respectively). The strain was becoming weakly through in- 

 breeding, and here died out. There is some suggestion here that non-melanic 

 is recessive to melanic, though some of the proportions are rather inexact. 



Xanthorhoe ferrugata (Coremia unidentaria). — A long series of experi- 

 ments, extending from 1894 to 1898, was undertaken by L. B. Prout with a 

 view to obtaining light on the curious colour-dimorphism of this species, 

 and the results have been published in considerable detail in the 

 ' Transactions of the City of London Entomological and Natural History 

 Society ' for 1897, pp. 26-34, and Tutt's ' British Lepidoptera,' vol. 5, 

 pp. 61-64, and summarised in a later memoir, entitled " Xanthorhoe ferrugata 

 and the Mendelian Hypothesis" (' Trans. Ent. Soc. Lond.,' 1906, pp. 525-531). 

 These showed, as Mr. L. Doncaster pointed out in an interesting supple- 

 mentary note (' Proc. Ent. Soc. Lond.,' 1907, pp. xx-xxii), roughly Mendelian 

 proportions on the assumption that the black form was recessive to the 

 purple. It seems to us curious, however, in spite of the large percentage 

 of deaths which introduced a factor of indefiniteness, that one pairing of 

 heterozygotes (No. 3 on p. 528 of the paper) should have yielded in Fi 

 11 specimens showing the recessive coloration as against only 6 showing 

 the dominant — the "expectation" being 4 recessive against 13 dominant, or 

 at best 5 against 12. At any rate, the species shows nearly complete 

 segregation, and will be a valuable one for future Mendelian research. 



C. domimda. — We may further mention that Mr. L. W. Newman, of Bexley, 

 a careful and successful breeder of Lepidoptera, has recently observed 

 * On p. 13, line 8, " 45 %" is a misprint for "40 %."— L. B. P. 



