Silkworm from Japan. 367 
This, when taken out of the cocoon at first soft and pale, 
soon hardens and assumes a dark-reddish or black hue. It is 
prudent to allow fifteen or sixteen days from the commencement 
of the cocoon before moving them, so as to insure a thoroughly 
perfect change. The pupa, in a normal state, hangs vertically ; 
it is provided with a reservoir in front containing a particular 
fluid, destined to dissolve the gum of the cocoon, to soften the 
threads and to moisten the body of the insect, thus facilitating 
the exit. This reservoir of fluid has been noticed by M. Guérin- 
Méneville to be peculiar to all those species which possess closed 
cocoons, viz., B. Mori, Pernyi, Mylitta, &c., and to be absent 
from all those species which have open cocoons, viz., Cecropia, Pyri, 
Cynthia, &e., and has been pointed out by him to belong to the 
Yamamai.* Nevertheless I have observed that the face of B. 
Cynthia is perfectly moist while emerging, and that after emerging 
a drop of fluid, giving a feeble alkaline reaction, stands on the 
palpi, and that the aperture of the cocoon is frequently left damp. 
From thirty-nine to forty days elapse from the formation of the 
cocoon to the exit of the moth. This magnificent Lepidopteron 
measures 53 to 6 inches from tip to tip; on emerging it will expand 
its wings suspended from the cocoon similarly to the habit of B. 
Cynthia ; its birth takes place normally from five to eight p.m., so as 
to be ready for flight that same night ; after a lapse of about three 
hours the moth expands its wings flat, as is the custom of that 
tribe; the ground colour of the wings varies much in individuals, 
but the yellow variety is the most constant in the male, and the 
brown variety in the female. The male is immediately recognised 
by his very broadly pectinated antennae. Like the Bombyx Cynthia 
the upper wing of the male is acutely falcate at the tip, but 
broader and blunter in the female. This formation, common to 
many of the large swiftly flying Lepidoptera, doubtless enables the 
male to fly with great rapidity and directness of flight, while the 
larger tip of the female is generally accompanied by a more 
broadly developed under-wing, destined doubtless to contribute 
mainly to the support of the body, which is heavy with its burden 
of eggs. The abdomen is slender and short compared with the 
size of the wings. The body and wings are on the upper surface 
of a brilliant yellow, but sometimes more or less grey, brown or 
dove-coloured ; the head, large, is always grey, spotted with white ; 
some angular and transverse streaks intersect the wings at about 
* Vide Mémoire sur le Bombyx Yama-Mai, par Mons. Guérin-Méneyille, 
