Restoration of the Silkworm. 145 
much signify, as for the present, at least, it is with that known 
and cultivated in Europe as an annual that we have to deal; but 
from a paragraph quoted by Mr. F. Moore from the ‘“ Account of 
the Ceremonies of the China Dynasty,” it would appear as if 
more than one species was under cultivation at the time when the 
« Account” was written, inasmuch as it contains an allusion toa 
second crop of silk, when it says,—* the officer who adjusted the 
price of horses forbad the people to rear a second breed of silk- 
worms in one season.” Now, whatever the Bombyx Mori may be 
when cultivated in Cashmere, Persia or Europe, it may un- 
doubtedly be made, in a suitable temperature, to produce an 
autumnal brood; this, however, refers to the worm after having 
been submitted to my experiments for two or three years, and 
when, indeed, it may be said to be fast travelling back to a state 
of nature. The same thing occurs likewise with regard to another 
species which is also an annual, as far as I can learn, in all coun- 
tries, except Mussooree, in the Western Himalaya; this is the 
Boro Pooloo of Bengal, and Bombyx textor (nobis), which, like the 
Bombyx Mori, yields an autumnal crop when treated in a particular 
temperature. This fact, indeed, has led some people to declare 
that the two are but varieties of the same species, and that in a 
state of domestication all may, by the application of certain tem- 
peratures, be made to yield several crops of silk annually. This, 
however, may fairly be denounced as pure nonsence, the occur- 
rence of the two crops arising solely out of the fact of our having 
in autumn a recurrence of the spring temperature, or what may be 
called a double season. Hence, since a particular degree of tem- 
perature causes the egg to hatch, whenever the season returns in 
which that temperature is produced, the young worm is of course 
excluded from the egg. It is quite possible then, and even pro- 
bable, that these species may originally have done the same in 
their native country, and the reason why they have ceased to be 
double-brooded in Europe and other localities is to be attributed 
solely to the uncongenial temperature, which is sometimes too 
high, at other times too low; and with respect to those species 
which are termed “monthly” worms, if it were really the case 
that the number of crops is due to cultivation in warm climates, 
it ought to follow that, when domesticated in a cold climate, the 
frequent succession of silk crops should become less frequent, and 
the worm give symptoms of reverting to its old habits. Such, 
however, I have not found to be the case; for although I have 
succeeded in obtaining two broods from Bombyx Mori of Cash- 
mere and B, teator of China, yet the small monthly.China worm 
