Silk-producing Bombycide. 315 
On the 16th of August the eggs, although still of a pale straw- 
colour, became somewhat dusky and exhibited the black head of 
the young caterpillar within the shell. 
On the 17th these eggs had become grey and of good colour. 
On the 18th they all hatched in a swarm, and I found that, unlike 
B. Mori, which ceases to hatch about midday, these continued to 
come forth during the entire day and night, until all were ex- 
cluded. 
When first hatched they are about 1, of an inch long; and 
after the first moult 3; inch; after the second moult 8, inch ; 
after the third moult 1,3, inch; and at maturity just before 
spinning 2.3, inches. 
I observed a curious fact with regard to some of these eggs 
that were Jaid on the 5th of August,—about 20 of them turned 
vinaceous on the 10th, while all the rest of the brood remained in 
statu quo. These coloured eggs were not scattered about among 
the others, but formed a small group by themselves. They did 
not hatch with the others, but remained in the same vinaceous 
state until the 3rd of October, by which time the others were again 
laying eggs. Yet I could perceive no difference in the worms 
afterwards, although there had been an interval of 30 days 
between the hatching of the two parties laid on the same day. 
This species continued to yield crop after crop even up to the 
middle of December, when many of the cocoons remained dormant, 
while others yielded moths which laid eggs that remained un- 
hatched, the weather being very cold and variable, and no leaves 
remaining on the mulberry trees. Here I think we have a clear 
proof that at least this monthly worm could never have inhabited 
a northern climate, but must by nature be entirely restricted to 
warm lowland regions in which mulberry leaves are procurable all 
the year round. 
It appears from some remarks of Mr. C. Blechynden that it 
was to this species and not to the Nistry (B. Crees) that allusion 
was made in Young’s Magazine of Agriculture, as quoted by 
Kirby and Spence, and the same gentleman observes that the 
name given to the species by the natives is “ Sina” or Chinese. 
He remarks as follows :—“ The worm mentioned by Kirby and 
Spence does exist and is known as ‘ The China worm ;’ it goes 
through all its changes from egg to cocoon in twenty-two days ; 
so it is nothing strange to have new progeny in a month. The 
period may be shortened by two or three days if the room occupied 
as a rearing-room is kept at a high temperature ; it breeds all the 
year round, but in the cold weather is longer in going through its 
AA2 
