398 Dr. Wallace on the Ouk-feeding 
more successful than in this country, were precarious and un- 
certain, and gave great anxiety lest the new race should fail in 
being successfully acclimatized. 
Dr. Chavannes, of Lausanne, who has devoted much time and 
attention to the rearing of silkworms, and who has successfully 
cultivated the Yamamai, is strongly of opinion that it is neces- 
sary to rear them out of doors on the living foliage; he writes, 
Revue de Sériciculture, 1864, page 85, “‘ This method of rearing 
the larvee,” (on boughs placed in water,) ‘may seriously com- 
promise the safety of the race. I have had experience in rear- 
ing three wild races of silkworms in Brazil and Europe, &c. 
The first generation so reared may do well, the second does 
badly, and the third not at all; all the worms perish. I would, 
in order to preserve them from danger as much as possible, rear 
the young worms during their first stage in a room on sprays 
dipped in water, but afterwards on the trees themselves, at the 
side of a wood, on boughs covered with gauze nets; protected 
by these nets there is nothing to fear from birds or insects, and by 
placing at the foot of each tree sawdust impregnated with coal- 
tar, the ants, their worst enemies, are kept away; for the same 
reason the branch which bears the gauze net should be wrapped 
round with cotton wool, dipped in coal tar. As to the sun, I am 
not afraid of it, if the larva has the shade of a few leaves.’ His 
resumé of 1864 is as follows :*—* Out of 900 eggs of Yamamai, 
640 hatched out, from the 21st April to the 26th. In their two 
first stages the worms were fed on boughs dipped in water, after- 
wards on the living trees, protected by metallic or gauze cages. 
Some worms remained on the boughs till the third stage; 200 
worms died the first few days without eating ; twenty-six died 
during their growth, viz., six at their full size; three had been fed 
on oak boughs dipped in water up to their third stage, and they 
died of the disease improperly called ‘pebrine;’ twelve were 
drowned in the water which had accumulated in the lower part of 
the gauze bags during their change; four or five were crushed 
during the changing of the gauze bays; three or four remained 
little and spun no cocoons. In all I had 414 cocoons. The most 
important consideration is the preservation of the eggs. What 
temperature is best? My eggs were kept from September to 
December 20th, between 48°—55°, F.; after that till March 10th, 
during fifty-three days, the temperature was 44°—46°; for seven 
® Revue de Sériciculture, 1864, p. 324. 
