AND COLLEGE, PUSA, FOR 1915-16 93 



<ditions are rendered more difficult by the unalterable pre- 

 judice of the rearers against purchasing " seed " in the 

 form of eggs, their desire to be assured of the quality of the 

 silk to be obtained leading them to refuse to buy anything 

 •except live " seed " cocoons. This means that eggs derived 

 from moths which have passed examination and are pre- 

 sumably disease free, must be hatched out and brought to 

 maturity, at the same time going through all the chances of 

 infection incidental to several weeks' life in artificial 

 surroundings, the resulting cocoons possibly re-infected 

 during maturation, being bought by the rearers and used as 

 seed. Until this prejudice is overcome by the establishment 

 amongst the rearers of more confidence in the rearing sta- 

 tions, the industry must necessarily labour under the dis- 

 advantages resulting from the chances of re-infection of 

 the seed in the manner above described. 



A further point of interest has been investigated and 

 sufficient evidence collected to warrant a certain amount of 

 confidence in the conclusion arrived at, namely that infec- 

 tion of the larvae so far as pebrine is concerned does not 

 take place at all after the fourth moult, with difficulty after 

 the third moult, but with comparative ease up to this 

 stage in the life cycle. This conclusion is necessarily only 

 a provisional one being based on a comparatively small 

 number of experiments, but should it be confirmed by 

 further observation it will simplify the precautionary mea- 

 sures in rearing by making it possible to relax them con- 

 siderably during the later stages of growth, when larger 

 quantities of leaf and greater space are required by the 

 worms. Incidentally it was found that the majority of 

 the larvse were not only able to resist infection altogether 

 when kept under optimal conditions so far as space, air and 

 food were concerned, but that in a large number of cases 

 the progeny of highly pebrinized moths failed to develop 

 disease at all, if reared under these favourable conditions, 

 others from the same brood but in unfavourable surround- 

 ings succumbing in large numbers. 



G '2 



