Silkworm from Japan. 409 
cold and damp, to suit Ailanthiculture ; in these it would seem 
that the culture of the Yamamai might be favourably earried 
on. 
There is this great consideration in favour of the culture of the 
Yamamai over the B. Cynthia, that the latter feeds on a plant which 
is comparatively unknown in Great Britain, having been introduced 
little more than 100 years into Europe; there are therefore no 
plantations of this tree ready made to hand, as is the case with 
the oak tree, and a knowledge of its cultivation has to be spread 
and taught, as well as of the insect that feeds upon it. But in the 
case of an oak-feeder, we have many acres planted with oak trees 
and many million separate trees in our lanes and hedges, as also 
in our parks and gardens. It is therefore within the power of 
every one to experiment upon and hecome acquainted with the 
beauties and habits of this valuable insect. The cocoons, more- 
over, are much more easily wound than those of the B. Cynthia, as 
they require only to be placed in boiling water to unwind easily, as is 
the case with the ordinary silkworm, B. Mori. I anticipate, there- 
fore, a great eagerness on the part of the British public, when they 
know a little more about it, to make acquaintance with the Bom- 
byx Yamamai, and that I may render their experiments less dif- 
ficult, I will translate some of the cautions and hints given by 
Mons. Personnat in his valuable work on the Yamamai,* supple- 
menting them also with observations of my own. 
During the egg stage.{ To avoid fermentation, spread out 
the eggs in a thin layer not more than } inch deep; and move 
them gently every ten days, in order to renew the layer of air 
around each egg. Autumnal heat does not expedite their coming 
out. Inthe autumn of 1863 my eggs were exposed to a temperature 
of 80°—86° without damage. On the other hand, his excellency 
the Marshal Vaillant exposed eggs during the winter, outside a 
north window, to all the inclemencies of the season, without de- 
triment. Sometimes the eggs adhere, and when the adherent por- 
tion happens to be that which the young worm nibbles away to 
make his exit, he is still unable to get out owing to the opposition 
of the other shell, and he perishes ; hence it is as well to separate 
gently every egg, by first moistening them and gently rolling 
* Le Ver a Soie du Chéne, Bombyx Yama-Mai, par Camille Personnat. 
+ At Trieste Mons. Raimondo, Tominz recommends (vide Reyue de Séri- 
ciculture, 1864, p. 224) to keep the eggs during winter in a dry temperature 
not exceeding 40°. Mons. Personnat recommends a temperature of 32°—é0°, 
Revue de Sériciculture, 1865, p. 65. 
