TROCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING 801 



responsible for the degeneracy of our races. Indiscriminate in-breeding 

 has produced loss of vigour, delicacy of constitution and deterioration 

 of the whole animal system and consequently the silk procured from 

 the Indian races is inferior to that of Europe, Japan and China. 



Selection in silkworm rearing means the ability so to choose cocoons 

 and moths for reproducing the progeny, that with proper care a high 

 standard of excellence will be obtained. If the improvement thus secured 

 ^oes on generation after generation it will result in still further improve- 

 ment. But when the selection is made carelessly and without judgment 

 the improvement thus obtained is likely to revert to its former level. 

 Judicious selection alone cannot improve a race without suitable nutri- 

 tion, breeding and environment. The four go hand in hand whenever 

 the improvement made is to be maintained and wherever further improve- 

 ment is desired. Selection takes a long time to lift a race to a high 

 standard of excellence and requires patience to maintain it. 



Cross-breeding has done great service in the formation of new races. 

 "The influx of new blood to a weak race is always an advantage. It 

 brings new vigour and renovating power in the constitution of the worms 

 and makes them yield silk superior both in quality and quantity. Cross- 

 ing gives an immediate increase of productiveness of silk but the result 

 is uncertain in later generations. Time and experience can only tell 

 whether the hybrid races which we have produced will continue to give 

 ■satisfactory results without degeneration. With iinivoltine races it 

 is possible to renew crossing every year as there are many univoltine 

 races which yield cocoons of the same colour, shape and size, and so an 

 infusion of new blood is possible in European countries. But this is 

 not the case with the multivoltine races of India. There are only four 

 or five multivoltine races which differ in shape, size and colour and if 

 a cross is effected between any two of them the shape and colour of the 

 cocoons of the mongrel race become different and it takes about six or 

 seven generations to obtain uniformity in colour and shape. Besides, 

 some of the eggs of the mongrel races turn grey and hatch irregularly 

 like univoltine eggs in some later generations and so it is not possible 

 to obtain good results from the race, for, by the time uniformity is 

 obtained, the vigour and renovating powers are gone. If our multi- . 

 voltine races are combined with the univoltine races, they become univol- 

 tine in the second and third generations and it takes about three or four 

 years to establish the multivoltine characteristics. Some hybrid races 

 may turn into pure multivoltine races by accident, but this cannot be 

 depended upon, 



Our experience is that all hybrid races are not suitable for all cli- 

 matic conditions. Again all hybrid races do not necessarily become 



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