112 SCIENTIFIC REPORTS OF THE AGRICULTURAL RESEARCH 



infection. Experiments were carried out at Shillong 

 during August and September; layings of eggs from Pusa 

 were divided, half being reared at Pusa and half at 

 Shillong; artificial infection was carried out at both places 

 and it was found that even in the first generation a consi- 

 derable increase in resistance to infection was obtained in 

 the hill-reared larvae. Eggs from the latter were trans- 

 ferred to Pusa both from infected and from disease- free 

 moths, and further resistance to infection in the plains 

 was noted in the latter, whilst in the former a smaller 

 percentage &. infected larvae resulted from the hatching 

 out of seed from the diseased moths; the infected larvae 

 also survived through a greater number of moults and a 

 larger percentage of them attained maturity than is usual 

 in such cases. It was also noted that the hill-reared worms 

 produced better cocoons. It is proposed to continue this 

 line of experiment and to recommend the institution of a 

 central seed station at Shillong to provide ameliorated 

 seed for the Indian incfustry . The revised method of exa- 

 mination of moths previously reported has been adopted 

 by various grainages in India; the Sericultural Superin- 

 tendent at Berhampore (Bengal) has reported favourably 

 on his experience of its use during the last season. It is 

 abundantly clear that owing to the use of multivoltine races 

 in India and the generally insanitary conditions under 

 which rearing is carried out it is essential for the rearer 

 to begin his season with disease- free seed, in default of 

 which the rapid cumulative effect of any small percentage 

 of disease initially present, in the course of rearing the 

 numerous broods characteristic of the multivoltine races, 

 will inevitably result in the failure of a fatally large 

 proportion of the worms. For this reason it is necessary 

 to adopt in India a much higher standard of purity in 

 the seed issued by grainages than is customary in Europe.. 

 A lecture on this subject was given at the Entomological 

 Conference held at Pusa in February, 1919. A memoir on 

 the mechanism of infection and the elimination of pebrine 

 in India is now in the press. 



