134 Silhvorms in India. [Vol. I. 



cocoon. Besides being 1 contagious, the spores preserving their power of 

 communicating the disease for considerable periods, it is also hereditary, 

 the eggs laid by a pebrinized female tending to produce pebrinized 

 worms. The remedy therefore consists in general sanitary precautions 

 to prevent infection, and in breeding only from eggs laid by such females 

 as are found "on microscopical examination, after they have laid their 

 eggs, to be free from corpuscles ; the eggs laid by moths which, prove to 

 be pebrinized being carefully rejected. 



b. Flacherie, which is known in Bengal as Jcala shira, is characterized 

 by the presence of a chain ferment 1 in the digestive tract of the silk- 

 worm and pupa ; the disease is contagious, and to a certain extent here- 

 ditary in that the larva? of moths which show symptoms of flacherie 

 have a predisposition to take the disease. The remedy therefore consists 

 in general sanitary precautions to prevent infection, and in the rejection, 

 for breeding purposes, of all eggs obtained from batches of cocoons, 

 which, on microscopical examination of the digestive tracts in a per- 

 centage of the pupse, show signs of the chain ferment. 



c. Muscardine, which is known in Bengal as china, is caused by a 

 fungnc, Botrytis bassiana, which appears as a white efflorescence on the 

 body of the worm some hours after it has died of the disease. The 

 disease is contagious, hut not hereditary, for, though the worm may be 

 so slightly affected that it is able to spin, it invariably dies before it 

 becomes a moth, while healthy pupse, being protected by their cocoons, 

 are not liable to be affected. The disease is spread by the spores, which 

 only appear several hours after the death of the diseased worm ; in the 

 speedy removal therefore of all dead worms from the breeding' trays, is 

 found an efficient preventive. 



d. Grasserie, which is prohably the same as the disease that is 

 known in Bengal as rasa, is of but little importance, and is never here- 

 ditary. Little seems to be known about it. 



Besides being subject to the above diseases, silkworms suffer from 

 the attacks of various parasitic and other enemies. In Bengal consider- 

 able loss is occasioned by the Tachinid fly 2 Trycolyga bombycis, which 

 lays its eggs upon the body of the worm. Its grubs, on emerging from 

 the eggs, bore into the tissues of the worm, and remain there until they 

 are full grown; they then cut their way out and betake themselves to 

 the ground, where they pupate. When attacked by this pest the 



1 This ferment is Streptococcus bombycis of Bechamp (Aticrozyma bombycis); oval 

 cocci, '5 /*. in diameter, occurring singly or in pairs or chains. They are found in the con- 

 tents of the alimentary canal, and in the gastric juice of silkworms suffering from flacherie 

 {inaladie de morts blanc, flaccidezza, or schlaffsucJit). — (Crookslwnk's Introduction to 

 Practical Bacteriology ; London, 1886.) 



2 For a detailed account of this pest see Indian Museum Kotes, Vol. I, No. 2. 



