304 Heredttji of MeJcuiism in Lcpidoptera 



In the results of the type x melanie crosses tlie same explanation is 

 probable. 



With regard to the inelanic specimens recorded from parents both 

 type, it seems that one of the 4 J 's had really paired with a black (/. 

 Pairing occasionally occurs immediately the wings have dried, and all 

 breeders of Lepidoptera know how difficult it is to exclude all possi- 

 bilities of error when dealing with large numbers of pupae. On the 

 much less probable of the t\vo original hypotheses, viz., that the 

 original (/ parent was melanie (hetei-ozygous), some of the 70 would be 

 homozygous, and this would the more easily explain the preponderance 

 of melanics in their offspring. 



h. A paper entitled "Melanism in Yorkshire Lepidoptera," by 

 Mr (i. T. Porritt'. 



A melanie female captured in 1904 deposited ova, which developed 

 into 6 melanie and 3 type sjDecimens. From the black moths a large 

 brood was reared, which included 75 per cent, black specimens, and from 

 these again a considei'able number were reared in which the percentage 

 of black was even greatei-. 



Mr Porritt has also repeatedly ci'ossed tyjje and melanie and found 

 the pi'oduce is about half and half of the two forms. These results are 

 easily reconcilable with the following experiment and the conclusions 

 drawn therefrcmi : 



In the autumn of 1009, on the advice of Mr Leonard Doncaster, 

 I connnenced an experiment on Odontopera bidentata in the hope of 

 discovering whether the heredity of the melanie form of this species 

 followed any rule or law. 



I commenced with a perfectly open mind on the subject, and in fact 

 had only a slight acquaintance with the various facts ,-uid theories of 

 heredity and variation. 



In November, 1909, 1 obtained 12 pupae, from which in April, 1911, 

 6 type and 6 melanie moths emerged. (Family 09.1). 



Two pupae were also obtained from a different source and produced 

 one type and one melanie .specimen — 09.2 (see 1909 table). 



Six pairings were made, but in only two cases were the offspring 

 successfully carried to maturity: — 10.2 and 10.3. 



In June, 1910, I (jbtained 24 larvae bred from two melanie parents, 

 probably both of 09.1 flimily. The resultant moths ai'e 10.4. 



' Trtiiis. Brit. Ass. lyOC. 



