382 Dr. Wallace on the Ouk-feeding 
wards collected out of the bath by means of a sponge, lest the 
Jarvee, falling down in their wanderings (which constantly hap- 
pened), should be drowned. ‘The eleven larvae born to-day were 
placed on freshly gathered oak boughs; the cut ends of them 
being plunged through a wooden tray into water contained ina 
jam-pot beneath; over the oak sprays were placed either glass or 
zine cylinders, open at one end and covered at the other with 
gauze. In the water I invariably dropped a small quantity of 
brown sugar and a few drops of liquor potasse ; this mode having 
been recommended to me formerly by Dr. Knaggs as tending, 
in his experience, to keep the sprays fresher, and render the food 
sweeter to the larve. The larva on the Ailanthus tree had not eaten, 
but had wandered; this was repeated for several days; and finding 
that he would not take to the new food, I transferred him to white- 
thorn to make trial of that provender. In the greenhouse the 
larve had eaten well, and seemed to have got on faster than those 
upstairs. Of the two larvae from lot No. 4, placed on a seedling- 
oak in greenhouse, one had eaten and the other not; the last 
seemed weak and ailing, did not move, and would not cling to the 
leaf; the oakling was therefore taken upstairs, placed in the bath 
and watered freely. The larve on the tree in the greenhouse 
now wander less, eat freely, and grow rapidly. During the day 
one larva was observed to have frass in his jaws, which he 
seemed to be trying to get rid of by working it up and down 
against the side of the leaf; after several attempts he was suc- 
cessful. TI came to the conclusion, which was afterwards verified 
by observation, that he had picked it from the anus with his jaws, 
having found a difficulty in getting rid of it in the usual way. On 
another occasion I observed the curled bristles at the side of the 
head made use of to detach dried frass which was attached to the 
anus. 
May 12th. Minimum temperature during the night 56°; at 9 
a.m. 57°, no sunshine, rain falling; syringed the leaves well ; 
the larve growing; the seven larve in the greenhouse doing well ; 
removed the excreta of several from the anus; still some tendency 
observed to wander. Two other larva, which came out to-day, 
were placed on white-thorn; the others that emerged were placed 
on oak sprays, gathered from the hedges. One larva was found 
to-day injured with a wound in its left side. 
May 13th. Cold, dry, no sunshine; five larvee emerged, 
they seemed smal] and sluggish, and one lay curled up a long 
time on the leaf, as if still inside the egg. Minimum temperature 
during night 54°, during day 52°, but it afterwards got up to 60°, 
