Silkworm from Japan. 399 
days, 41°—44°; for ten days, 46°—49°; during the month of 
March and to the 15th April, 46°—49°; afterwards to the 2Ist, 
4.1°—50°, F. I think these temperatures too high, and intend to keep 
them this winter as near as possible 39°—41°; for on the 2lst 
April I had a premature birth in my cellar at 50°, and I have 
noticed, as Mr. Hardy did, that worms born at that temperature 
die soon after birth. To that low temperature, at the moment of 
hatching, I attribute the loss of the 200 worms. The eggs ought 
to remain, after being removed from the cellar, for five or six days 
at a temperature of 55°—60° before hatching, the better to avoid 
the mortality ; the eggs should be moistened two or three days 
before hatching, by being placed on blotting or bibulous paper 
“moistened. I have shown that to feed them on boughs dipped in 
water is injurious, for the worms thus nourished up to the fourth 
stage perished at the end of the fifth. I propose another year to 
place the young worms at once, or immediately after the first 
moult, on the young oak trees. The caterpillar seems able to 
support a very low temperature, for this year has been unusually 
cold and wet; during June we had several mornings as low as 
59°. The time occupied in the several stages has been as fol- 
lows :—First stage, 11 days; second, 10 days; third, 7 days; 
fourth, 12 days; fifth, 18 days; in all 58 days. Of sixteen 9 
exposed in the woods, where I set at liberty two g for every ¢, 
all laid fertile eggs. Out of fifty-four pairs placed separately in 
gauze cages, in two-thirds of them coition was successfully per- 
formed. Ina large cage, where many were at liberty together, 
about half the eggs were sound. I have observed coition to take 
place about 9 o’clock p.m., between two recently-emerged moths, 
Thrice have I observed coition repeated a second time by the 
males. If the sides of the cage are of metal and not of canvass or 
gauze, the feet of the males are injured by the second night. 
About 110—112 eggs weigh a gramme.” * 
I will now translate parts of a very interesting document pub- 
lished recently in the Bulletins of the Imperial Society of Acclima- 
tization. It is a Japanese manual on the culture of the Yamamai, 
translated into Dutch by Dr. Hoffman, and again translated into 
French by Mons. F. Bleckman, the interpreter of the French 
* According to Mons. Guérin- Méneville’s experiences in 1862, with the 
eggs that first came over from Japan, 140 weigh about a gramme, and the 
average weight of 100 eggs is 070 grammes. Vide Revue de Sériciculture, 
1863, p. 34, 
