394 Dr. Wallace on the Oak-feeding 
an insufficient manner, so that the digestive functions are im- 
paired, and in consequence of the blood being impoverished, a 
change takes place in the fluids favourable to the development of 
fungoid disease, and the result is an epidemic accompanied by great 
mortality. The results of my experiments, and of my experiences of 
a similar if not the same malady among the Cynthia larvee, seem 
to lead me to the following general conclusions: that it is neces- 
sary to supply the very young larvae with young succulent leaves— 
that they will bear a moderate amount of cold for brief periods 
with impunity—that they avoid the direct sunshine, but like its 
warmth diffused through the natural leafy shade—that moisture is 
grateful to them at all times and is necessary for their existence— 
that a quick growth is most favorable. 1 have found that the 
Cynthia larvee when retarded in their changes by cold and wet 
weather, as has been the case this last summer, are more liable 
to this and other epidemics. Dry hot weather is prejudicial to 
the larvee: for that reason I should think they are likely to do 
best on large oak bushes planted sufficiently close to allow of 
shade among the interlacing boughs. Similarly the larva of 
Notodonta trepida rejoice in the cool shade of the north aspect of 
dense forest trees. For that reason the climate of Ireland would 
probably prove highly favourable to the cultivation of this species. 
Lastly, I am convinced that they would thrive better out of doors 
on the trees than in confinement. ‘The nearer we could approxi- 
mate their life to the natural wild state, the more we should re- 
pair their constitution weakened by a long journey, and by a 
faulty system of education. 
I will now relate some of the experiences of French experi- 
menters. In the Revue de Sériciculture for 1863, p. 352, &c., 
is an account of the complete success of the first trial of Mons. 
Personnat at Privas, Ardéche: he had received a gramme of 
eggs from the Society of Acclimatization, part of those brought 
over by Mons. Pompe van Meedervoort; there were fifty fertile 
egus, the rest were dried up; he had provided himself with young 
oaks in pots, but the birth of the worms coincided with the appear- 
ance of the leaves in his neighbourhood. The eggs were placed 
in a paper tray amongst.the young leaves, so that the newly-born 
larvee might at once crawl on their food without being touched ; 
they began to appear on the 11th April and continued to do so up to 
the 28th; out of forty-five worms so hatched he obtained forty- 
four cocoons, one was lost by accident; he tested the wandering 
powers of the newly-born larve by making them walk the distance 
