No. 3. ] Silheorms m India. 16; 



These must be carefully removed from the leaves that are given to the silkworms, and 

 the leaves themselves washed in water. It is at seasons like these that the leaves of 

 a variety of trees are used as substitutes for the favourite food of tbe worm. Large 

 numbers of the worm are lost by disease, of which neither the nature nor the remedy 

 is known, 1 but which probably has its origin in uncleanliness. No care is taken to re- 

 move the excreta, nor are tbe dead worms regularly rejected. The native account oP 

 the disease is simply that the worm ceases to eat and withers away. Some good effects 

 are said occasionally to follow from sprinkling water, in whicb tulsi leaves have been 

 steeped, over tbe worms among which this disease has made its appearance. The 

 ichneumon fly is a deadly enemy. Its bite, 2 which leaves a black mark, usually proves 

 fatal to the worm at the next molting ; and if tbe wound has been inflicted after the 

 last molting, the worm spins a smaller cocoon, and dies before it is completed, leaving 

 the eggs of the fly to hatch inside the cocoon. 3 Rats are still more destructive, some- 

 times sweeping off an entire brood in a single night. The cultivator is careful to ab- 

 stain from praising his crop of worms, lest any of these calamities should overtake 

 them. 



" Tbe number of moltings is four, known locally as lidludia, duirJcdta, Unirhdta, 

 and chdrikata ; the first term denotes the yellow colour of the worm, the three others 

 merely mark the order of the moltings. Mr. Thomas Hugon, who held tbe office of 

 Sub-Assistant (corresponding to the present office of Assistant Commissioner) in the 

 Nowgong District, contributed a very carefully written paper upon tbe silkworms of 

 Assam to the Proc. As. Soc. Bengal for 1837, whence the following description of 

 the worm is taken : ' The caterpillar is first about a quarter of an inch in length, and 

 appears nearly black.' (The colour is, perhaps, more exactly described as a blackish 3'el- 

 low.) ' As it increases in size, it becomes of an orange colour, with six black spots on each 

 of the twelve rings which form its body. The head, claws, and holders are black; after 

 the second molting they change to an orange colour ; that of the body gradually be- 

 comes lighter, in some approaching to white, in others to green, and the black spots 



1 Some alcoholic specimens of eri worms which had died of a disease reported on by 

 Mr. Mackenzie as having proved most fatal to worms in Cachar, were sent to the Indian Mu- 

 seum, in August 1889, by Mr. R. S. Greenshields. On microscopic examination of the di- 

 gestive tracts of some of the caterpillars, tha chain ferment Streptococcus bombycis, which 

 is characteristic of Flacherie in the mulberry silkworm (see p. 146), was made out 

 in one instance. Ferments of this kind are always very difficult to make out in al" 

 coholic specimens, and the not finding it in large quantities does not therefore affect the 

 practical certainty that the disease is Flacherie, while Mr. Mackenzie's description of the 

 symptoms, which were precisely those of the Flacherie of the mulberry silkworm, leaves no 

 room to doubt that the disease was actually Flacherie. This discovery is somewhat remark- 

 able, Flacherie being a disease which, in the case of the mulberry worm, is so intimately 

 connected with the fermentation of the mulberry leaf, that it might have been supposed 

 that it would not attack the eri worm, feeding as it does on a different plant. Pasteur's 

 remedy for Flacherie in mulberry silkworms will no doubt be found to be applicable to 

 the eri (see p. 146). A further and more careful examination of the specimens has since 

 been made, but the ferment has not been recognized in the sections prepared. The obser- 

 vation, therefore, of its presence requires confirmation. 



3 The ichneumon fly destroys the caterpillar, not by biting it, but by depositing an 

 egg, which develops into a grub which feeds on its tissues, the caterpillar succumbing to 

 the internal injury caused by the grub. 



8 The eri worm is also attacked by tbe Tachinid fly, Trycolyga bombycis, a parasite 

 which is most destructive to the mulberry silkworm in Bengal. A detailed account of it 

 is given in Indian Museum Notes, Vol. I, pp. 77-88. This is not improbably the " Ichneumon" 

 described by Stack. 



