THE PEACOCK BUTTERPLY. 121 
caudal wings. There are on each of the lower wings 
a large oval sesquialterous eyelet, of deep black, 
surrounded by an ash-coloured ring, bounded on its 
outer extremity by another ring of black: the spots 
on the centre are deep blue, with a white semi- 
lunar one at top. 
This insect is subject to considerable variety, in 
some of which the margins are deep brown. ‘The 
under side of this butterfly is almost entirely black. 
The caterpillars of the Papilio Io are produced 
from eggs which are deposited in the spring of the 
year on nettles. The larve are of a fine deep black, 
thickly beset with sharp spikes, and finely powder- 
ed with minute white specks. 'The belly legs are 
of a tawny brown, and the others black. They live 
in society, and are seen in the early part of summer 
feeding on nettles. Shortly after the little animals 
are hatched, they begin to spin for themselves a large 
and commodious web, into which they fly for shelter 
on the approach of rain, which the exquisite sensi- 
bility of their nervous system enables them to fore- 
see a considerable time previous to its falling; they 
therefore may he depended on as excellent prognos- 
tics of changes in the state of the atmosphere. They 
also take refuge under this covering during the 
night. 
When they have attained their full growth, which 
is about the beginning of July, they seek out some 
proper place where they can safely assume their 
