374 Dr. Wallace on the Oak-feeding 
dead. _ I was about to stick a pin into it when | thought it moved 
—certainly the head was no longer in its former position. It was 
then placed in the sun, when it began to move briskly; it was 
placed by itself in a box with two drops of water; it however 
seemed to have received some damage, as it could not craw], but 
lay on its side, prematurely born, and it subsequently died. On 
the 26th, finding the temperature elevated nearly to 60° during 
the day in the porch where the eggs were kept, and that the oaks 
in the lanes were now breaking, and that the young larvee which 
I had examined in the shell were lively and vigorous, it seemed 
that the time had arrived for the natural birth of these creatures ; 
knowing, however, that a little moisture would accelerate birth, 
and that the moisture incidental to the month of April had been 
sedulously withheld, and thinking that a pill-box enclosed inside 
another tin box would be an unfavourable situation for the birth 
of my little favourites, I determined that the hour was now come in 
which it was needful no longer to retard the eggs, but to place 
them under the most favourable conditions for hatching out. 
Doubtless they would have remained some time longer in the 
boxes without hatching, but I am inclined to think, from the 
result of various experiments made with eggs of B. Cynthia as 
well as with those of Yamamai, that to retard the development of 
egos beyond a natural time, is to injure their vitality, and conse- 
quently to diminish the chance of rearing healthy progeny. There- 
fore, about 10 a.m., | removed the boxes into a room upstairs, 
used by me as a dressing-room, 13 feet square and 9 feet high, 
having an Eastern aspect, where the temperature stood at 61°. 
Having counted the eggs in the three healthy lots, I found 80 in 
the lot sent me by Mons. Guérin-Méneville, and 142 eggs sent me 
by Mons. Personnat divided into two lots of 71 each: these three 
lots were placed on separate pieces of bibulous paper, two or three 
pieces of paper under each lot, on a wooden tray ; over each lot 
of eggs was placed a glass funnel, open at the small end; the eggs 
were not placed in the sunshine, but the window was open. It 
was a sunny day, with a gentle east wind; the bibulous paper 
was well moistened from outside the funnel, and, as a necessary 
consequence, the eggs became moistened also, and a moist atmo- 
sphere was kept up in the interior. At 3 p.m. I found one larva 
born—it moved slowly and seemed weakly ; it was on the paper 
close to its empty egg-shell, which was removed to avoid con- 
fusion. An oak spray (from one of the trees in pots which had 
been forced) was passed through a hole cut in a wooden tray, 
