The effect of moisture upon the silk of the hybrid Philosamia (attacus) ricini boisd. ♂ × Philosamia cynthia (Drury) ♀

Onèra A. Merritt Hawkes
1916 Journal of Experimental Zoology  
Philosamia ricini and of P. Cynthia from Ning-po were crossed in 1914 in order to study the method of inheritance of certain spots on the larva, the colour of the cocoons, and the arrangement of the long white hairs on the abdomen of the moth. The results of the preliminary work on cocoon colour are given in this paper, no reference being made to the still unfinished work on the larva and moth. When the cocoon colour work was undertaken, it was hoped that the results would help to explain the
more » ... lp to explain the lack of coincidence between the work of Kellogg and Toyama on the inheritance of colour in cocoons. The breeding, thus far, has thrown no light upon the method of inheritance, but, if the cocoons used by them, are as much affected by moisture as the hybrid here discussed, their results may have to be considerably modified. Philosamia ricini is found wild in Assam, but has also been domesticated to a considerable extent in that province, and to a smaller degree, in other parts of India. A careful study of the life history has been made at Pusa, India. The form there cultivated is not pure, some larvae being spotted instead of spotless, and some of the cocoons being a pale fawn instead of a pure white. Every effort is, however, made to keep the broods as nearly as possible like the wild form, which has a spotless larva and a pure white cocoon. Owing to the uncertainty of the Pusa stock, the specimen used in this cross was chosen from a batch of white cocoons collected in the Assam forests. In order that there should be no doubt ;bout the stock, Mr. J. H. Watson and myself, mated males and females of this batch 51
doi:10.1002/jez.1400210104 fatcat:fdtzc62xdbf3zkfm3wgsnw73au