Sericulture* 



[244 



[September, 1909. 



occurring inside the cocoon. The full- 

 grown worms, when ready to spin, 

 become restless and move about ; they 

 are then placed in baskets filled with any 

 convenient dry packing material, e.g., 

 the finely shredded wood used in pack- 

 ing delicate goods, wood-shavings, torn 

 paper, dry straw or dry leaves. Into 

 this they crawl and spin cocoons, first 

 making a foundation, then spinning the 

 regular cocoon inside. This oocupies 

 about three days ; the cocoons are left 

 for at least a week and are then picked 

 out by band and laid out before the 

 moths emerge. The moths emerge with 

 crumpled wings and gradually spread 

 their wings ; they void a large drop of 

 excrement, so it is advisable to let them 

 crawl up off the cocoons. The moths 

 are then collected into baskets, where 

 they couple. After twenty-four hours, 

 the couples are separated, aud the 

 females put in other baskets to lay eggs, 

 after which they die. The moths make 

 no attempt to escape, and there is no 

 need to confine them ; but coupling and 

 egg-laying are facilitated by placing the 

 moths in baskets, to which they can 

 cling and in which the light is not too 

 bright. The moths lay, as a rule, from 

 200 to 800 eggs each, and if a large brood 

 is required, all the eggs obtained may 

 be kept for hatching ; if not, only those 

 from the best moths or only those laid 

 on the first night (80). 



In Pusa, seven broods are obtained 

 during che year ; in hot weather about 

 forty-five days is the total length requir- 

 ed for the egg, worm, cocoon and moth 

 stages- This increases to as much as 

 eighty days in the cold weather of 

 January and February, when the worms 

 feed less rapidly, and the moths take 

 longer to emerge from the cocoons. The 

 worms are resistant to all weather but to 

 a dry, parching heat ; in the hot weather 

 when the west winds bring a temperature 

 up to 110°F. with an extremely low humi- 

 dity and an atmosphere laden with fine 

 dust, the worms are less resistant to 

 disease and may be unable to spin 

 cocoons or to emerge as moths. At this 

 time large numbers also fail to pass 

 through the first moult. This is especi- 

 ally so if one has been rearing from too 

 small an initial stock; "in-breeding" is 

 as bad in this species as in others, and 

 if there is a period of dry, hot weather 

 to be passed through, the stock should 

 be as vigorous as possible. It is, there- 

 fore, advisable to be able to introduce 

 fresh stock at intervals, as can be readily 

 done by obtaining fresh seed. 



The insect at Pusa is not subject to 

 any of the usual silk worm diseases, but 

 has a peculiar disease, allied to flacherie, 



but with symptoms and characters 

 which, in the opinion of the Imperial 

 Mycologist, separate it clearly from that 

 disease, The experience at Pusa has 

 been that it is better not to rear it at all 

 during the hot, dry months or, if that is 

 desirable, to rear only from good stock. 

 As a supply of seed from Assam is now 

 readily procurable, there is no reason 

 for attempting to rear during unfavour- 

 able seasons. In Assam a parasitic fly 

 attacks the worms, but if only eggs are 

 imported and not cocoons, this pest will 

 not be found and does not occur gener- 

 ally in India. The insect grows most 

 favourably in a moist climate, whether 

 hot or not, aud could be grown during 

 the rains practically all over the plains. 

 It is unsuited to the plains of Northern 

 India during April, May and June. 

 Starting on July 1st with 1,000 eggs, one 

 would have 900 moths by August 15th, 

 yielding about 80,000 eggs, which would 

 give a very large brood ; the rate of in- 

 crease is so large and rapid that one can 

 easily start afresh every season. 



Appliances,— In rearing, very few 

 appliances are required. The rearing- 

 house may be any roofed structure of 

 grass and bamboos with earth-floor. A 

 large supply of trays, made of split 

 bamboo or similar material are required, 

 some with fine mesh, some with coarse, 

 open mesh ; the former may be smaller. 

 In these the rearing is done, and one 

 may keep the largest worms also in large 

 rectangular trays of any size up to four 

 feet by three feet. For the cocoons and 

 moths, baskets are required and a supply 

 of paper, shredded wood, straw or other 

 clean material for the worms to spin iu. 

 We have also used the special emergence 

 trays, but it is not essential. The trays 

 are placed upon machans of split bam- 

 boo which may be covered with matting. 

 The legs of the machan should be 

 smeared with some sticky material if 

 ants are a trouble. 



Food-— The worms are wholly fed 

 upon castor leaves, plucked as required, 

 and the castor plants must be available 

 close at hand. For young worms small 

 leaves are used, but later the large 

 coarse leaves are required. Varieties of 

 castor have been collected at Pusa from 

 all parts of India ; some are better leaf- 

 yielders than others, but all are eaten, 

 the bronze or red ornamental variety 

 grown in gardens being, however, dis- 

 liked. The varieties in cultivation are 

 apparently all suitable, some yielding 

 more leaf than others. We are not here 

 discussing the question of growing the 

 worm on a large scale for factories, but 

 rather of utilising available castor leaves, 

 at present of little value, for producing 



