THE SILKWORM ITS DISEASES AND IMPERFECTIONS. 69 



Common Mulberry Silkworm, Bombyx mori. But this is not the 

 only Bombyx which feeds on the mulberry and is domesticated. 

 In India several other species are reared, all mulberry feeders, 

 which were for a long time confounded with B. mori. Of these, 

 however, none produce such large cocoons nor such good silk 

 as the common species. They differ from it, too, in the number 

 of broods produced in a year. B. mori always produces one 

 brood only, and is therefore called an " annual ; ' most of the 

 other species produce two, three, four, six, or even eight broods 

 per annum, and in the commercial world are, for that reason, 

 distinguished as " bivoltins," " trevoltins," " quadrivoltins," etc. 

 In the case of bivoltins, the eggs of the first brood hatch very 

 soon after being laid, to produce the second, the eggs of which 

 remain through the winter and yield the first brood of the 

 following year. When more than two broods are produced in 

 succession in the same year, the life of each brood extends over 

 a shorter period, and the number of moults is reduced to three 

 instead of four. Notwithstanding the large number of broods 

 produced yearly by some of the " polyvoltins," the " annuals ' 

 are found to be the most profitable, and are therefore much the 

 more extensively reared. 



Bombyx textor, a species domesticated in S. China and Bengal, 

 is, like B. mori, an annual ; it produces usually a white cocoon, 

 more flossy than that of the common species. B. crcesi, the 

 Madrassee, is cultivated in Bengal, having been introduced from 

 China. It yields seven or eight broods in the year, and forms 

 golden yellow cocoons. B.fortunatus, the Dasee of Bengal is 

 also a polyvoltin, and is noted as making the smallest cocoon 

 of all. The silk is yellow. B. Arracanensis, the Burmese 

 silkworm, is domesticated in Arracan, whither it is said to have 

 been introduced from China ; it spins a beautiful yellow or white 

 silk, not quite so glossy as that of B. mori, and yields several 

 broods annually. All these species are domesticated mulberry 

 feeders 



CHAPTER V. 



THE SILKWORM ITS DISEASES AND IMPERFECTIONS. 



SILKWORM rearers usually reckon that, granted good "seed," there 

 are five requisites to success in their employment, especially if 

 large numbers are operated on. These are, first, uniformity of 



