Silkworm from Japan. 395 
of a metre (nearly 40 inches) before reaching their food, and 
ascertained that they could do this with impunity, and that in 
their very young state they can remain some little time without 
food. The larvz were fed on sprays, placed in vases of water, 
from young oaks of the species Q. pedunculata and also Q. pubes- 
cens, but the pubescence of the latter renders it less suitable. In 
the fourth stage they were sprinkled with water daily in the 
morning, and in hot weather twice daily. The first cocoons were 
begun on June 25th, seventy-four days after the birth of the first 
worm; the cocoons were all finished eighteen days afterwards, 
forty-two very fine, one small, and one imperfect, the worm having 
been twice disturbed while spinning; the moth which emerged from 
this one was a very fine one, and Mons. Personnat was enabled to 
observe in the cocoon the successive changes: that into pupa took 
place on the 19th day after spinning; two days afterwards the 
pupa turned dark-brown; the receptable for the dissolving fluid 
situate on the fore part of the head was large and light-coloured, 
and contained evidently a large quantity of fluid. 
By retarding the first formed cocoons, and hastening the last 
made by placing them in a warm situation, he diminished the 
difference of eighteen days in the time of spinning their cocoons 
down to ten; the latter came out thirty-eight to forty days after 
commencing their cocoons, the former in from forty-four to forty- 
seven days; the first were males. In two days he had six males 
and two females. The cocoons were placed in a case having 
canvass sides, forty inches by twenty, and about twenty-four 
inches high, which was sprinkled daily with water to keep up fresh- 
ness and a slight moisture. The second morning Mons. Personnat 
ran to see the Yamamai; there was no trace of coition; the 
males had battered their wings; the females, resting against the 
canvass, seemed to have been untouched. He immediately made 
arrangements to spend the night in the room, but saw nothing 
except the birth of three males and two females ; the next night he 
went at midnight, but on his entrance the light caused such a com- 
motion in the box that he found all the moths were at the bottom 
frightened. The next night at 1 a.m., having arranged the light 
outside, so that only a few rays could penetrate, he witnessed two 
fresh pairs in coition; he retired carefully: the next morning there 
was no trace of what had happened. This very short period of 
coition seemed strange; nevertheless, it was proved to bea fact by 
subsequent experience. In one couple which were watched it 
lasted from 11 o’clock toa } past 1 ; the eggs of this pair were kept 
