Silkworm from Japan. 363 
instinct or requirement, to enable them ina wild state successfully 
to reach their food, which may, if the egg be deposited at the base 
of the tree, be situate at a considerable distance. 
It would appear that there is a considerable thirst and desire 
of drinking in these larva. Directions are given by those ac- 
quainted with their habits, to moisten the oak leaves twice a day, 
as if by rain, and I have observed that this guasz rain has a ten- 
dency to check the vagabondizing, for the larvee may be observed 
to place their heads down to the drops and drink them up, to all 
appearance greedily, as if moisture were very necessary to their 
existence, and then to repose in the mode common to the Bom- 
byces, resting on the hind claspers, the fore part of the body thrown 
upwards into a curve, the head deflected downwards, and the pro- 
legs tucked together underneath. 
Another observation, which soon forcibly strikes the possessor 
of these larve, is the small quantity they consume in their early 
life, very unlike the larve of B. Cynthia, whose appetite is most 
voracious, and whose growth is rapid in proportion; but these 
larvee eat very little, and consequently at first grow very slowly ; 
this is probably so ordered lest the unfolding oak buds in early 
spring might fail to furnish sufficient provender. 
About ten days after birth the larva measures 2 of an inch. 
It is now fuller in the body and eats more; the green tint now 
predominates over the yellow ground colour; the belly of the 
larva is of a transparent dull green; the tubercles on each seg- 
ment have a broad, yellowish-green base, which gives a lighter 
tint to the dorsal aspect ; the head is oak brown, a broad patch of 
the same colour is continued to the second segment in the mesial 
line, flanked by two lateral tubercles, which project like black 
warts, emitting white spines. From the two dorsal rows of tu- 
bercles spring curling dark spines, the four lateral rows emit 
spines of a light colour. The first moult of my oldest larva, 
which was born April 25th, took place May 22nd, an interval of 
twenty-two days, whereas in 5. Cynthia the first moult or change 
of skin takes place on the seventh day after birth, or even earlier 
in vigorous larvee and warm weather; the larva prepares for his 
moult by spinning a little silken web on the under surface of the 
leaf, and, fastening thereto the hind claspers, it remains motion- 
less and of a dull colour for three or four days ; then the skin is 
rapidly cast off, and it reposes in its new glory for some hours to 
harden the head, feet and external membranes. Altter the moult 
the larva presents quite a different aspect, its length is 3 of an 
inch, its colour a vivid grass-green, studded with six rows of 
