Silk-producing Bombycide. 311 
worms attain a length varying from 2 to 23 inches, as is the case 
also at Mussooree. 
As regards the colour of the silk, nothing could more strongly 
support my view that white is a sign of weakness and degeneracy. 
In Italy, we are informed, there are generally nine white cocoons 
in every ten,—but when cultivated in France bright golden 
yellow is the predominant colour; this is undoubtedly an effect 
of climate, showing that the warmth of Italy is less adapted to 
the health of the insect than the cooler temperature of France, 
which in some districts is nearly the same as that of Mussooree, 
where precisely similar results have been observed. The eggs of 
this species, hatched in March, 1864, from the deposit of May, 
18638, gave seventy-eight black to thirty-one white worms, in a 
batch of 109, whereas in 1868 eggs procured from Bengal produced 
white worms without a single exception. The cocoons spun in 
1863 by the Bengal worms were all white, with the exception of 
about half a dozen, whereas in 1864 there was not one white 
cocoon, all being of a bright golden yellow. In China, as in 
Bengal, the usual colour is white, with an exceptional sprinkling 
of yellow cocoons. Here we have the effect of climate distinctly 
marked, and showing that while a high temperature produces 
both white worms and white silk, a temperate climate, by impart- 
ing strength, produces dark worms and yellow cocoons. 
The worm which in France gives permanently a white cocoon, 
and which was imported from China into the ‘ arrondissement 
d’Alais,” would appear to be distinct both from B. textor and 
the other two varieties; so that if No. 1, or the Milanese 
worm, be our Boro-pooloo, as I suspect is the case, and Nos. 2 
and 4 are true B. Mori, then No. 3, with the permanent white 
silk, is in all probability a distinct species. 
The changes in the appearance of the caterpillars of B. textor 
are precisely similar to those observable in B. Mori, and need not 
be repeated; when first hatched, the worms of B. textor are 
rather black than brown, and alihough in the after stages there 
is in the colouring and marking of the two species no really tan- 
gible and well-defined distinction, yet at the same time there is 
to the eye a perceptible difference in the shade of colouring, 
which is darker, more prononcé, more equally diffused, and more 
of a neutral tint in B. texlor than in B. Mori; the latter, besides 
attaining to a far larger size and forming a totally different 
cocoon, has the dark parts less purplish and not so generally 
diffused. These remarks, however, pertain to the black worms 
only ; the white ones differ in no respect except in size. 
