386 Dr. Wallace on the Oak-feeding 
of the ova, otherwise some persons at least might have been for- 
tunate enough to rear the larva. But another cause clearly 
impaired the chance of success, viz. the large proportion of 
unfertile eggs, as manifested by the large proportion of those 
which contained no trace of larve, which indeed ought to be 
fully formed one month after the egg is laid. Hence I think it 
is clear that the eggs were in the first instance an unhealthy lot ; 
and secondly that their passage to England, and subsequent retar- 
dation in too cool a place, had taken away the remaining vitality. 
By recording this unfortunate result I may warn others from 
a similarly unhappy treatment of the eggs of this valuable race. 
May 19th. A warmer night ; minimum temperature upstairs 54°, 
in greenhouse 49°; at 9 a.m. 65° upstairs, in sun 90°, in shade 
60°. Inthe greenhouse three were dead ; I was certain that many 
larve in the greenhouse were missing, either having wandered or 
been eaten by spiders; those on the sprays were doing well, but 
rather restless. 
May 20th. Minimum temperature in the greenhouse 53°, up- 
stairs 58°; at 8 a.m. 62°; at 10 a.m. 70° in shade, in sunshine 
97°; very warm morning, the sprays getting stale, and the larve 
wandering. I occasionally found empty eggs and no larvee under 
the funnel, so that it is probable that the young larve hatched 
during the night and crept out of the top of the funnel, and wan- 
dered over the table; changed the sprays to-day ; two more 
deaths; the leaves of the oak trees in pots very dry. 
May 2Ist. Kept my blind down this morning ; temperature 
upstairs about 60°; only two larvae emerged; one larva was 
sucked in the greenhouse during the night by a spider; four 
have now moulted for the first time. Placed the sprays under 
bell glasses to keep the food moist, but these were removed the 
next day as not permitting sufficient ventilation; one egg of 
No. 4 hatched out a small shrunken weakly larva, which was 
placed in an air-tight glass bottle with some dry food ; this, how- 
ever, had withered by the next morning, when the larva was 
placed on a seedling oak having tender leaves ; the larvae were now 
brought in from the greenhouse by degrees, and removed upstairs 
for two reasons; one, that it was too hot for them by day, the 
other that it was found impossible to kill off all the spiders in the 
greenhouse, so as to prevent their destroying the larvee. 
May 22nd. Minimum temperature during night in the green- 
house 53°, upstairs 57°; at 8 a.m. 62°; at 9 a.m. 65° in shade, in 
sunshine 100°. Nine have now moulted for the first time; the food 
