6 SOUTH-AFEICAN BUTTEEFLIES. 
by intricate raised or impressed sculpturing of the most varied pat- 
terns. Their colouring also varies, and is often not uniform, but 
exhibits contrasted hues in the form of spots or bands.^ The number 
produced by the individual mother is usually large ; and they are laid, 
singly or in smaller or larger groups, on the leaves, twigs, or trunks of 
trees for the most part, — a viscid fluid which invests them on exclu- 
sion usually in hardening glueing them to the surface on which they 
are deposited. 
On emerging from the egg, the young lepidopterous Larva or 
caterpillar is sufficiently advanced in general structure, and in the 
development of its mouth-parts especially, to enable it at once to 
begin a more or less active independent life of voracious eating 
and correspondingly rapid growth. The nature of the integu- 
ment (which, though not so hard as that of the perfect insect, is, 
nevertheless, the external skeleton to which the muscles are attached) 
is such that it does not admit of gradual accessions to suit the 
growth of the animal, but is only so far accommodating as its 
natural elasticity allows. It follows that, at a certain point of the 
animal's increase in bulk, the too limited investing skin must be 
got rid of, and one of more capacity secreted in its stead. The cater- 
pillar temporarily abstains from eating, and its skin becomes faded, 
dry, wrinkled, and detached as the new one is developed beneath it. 
The process of detachment is aided by the dilating and contracting of 
the segments, and by various other motions of the larva ; and at length 
the old integument splits dorsally, and the insect emerges through 
the rent. The moult is a most complete one, extending to the head 
and legs, and even including the fine membranes of some of the prin- 
cipal internal organs. The new external skin (which often differs in 
colour or marking from the discarded one) soon hardens, and the 
caterpillar resumes feeding with increased zest, sometimes (as I have 
seen in Chcerocampa Celerio), in the first place, devouring its old skin. 
This process of moulting has been recorded to occur from three to as 
many as ten times, but it appears seldom *to take place more than five 
times. When the caterpillar has attained its full size, after some days 
it finally leaves off eating, and sets about the necessary preliminaries to 
assuming the pupa or chrysalis state. It commonly shows much rest- 
lessness at this time, wandering about in search of a suitable retreat ; 
and in those kinds which have smooth, brightly-coloured skins there is 
often a remarkable change to dull and sombre hues. It is now that 
the large reservoirs of silk are chiefly drawn upon, although the 
amount employed by members of different groups varies very greatly, 
from the mere disk to which the caterpillars of many butterflies hook 
their last segment to the full cocoon fabricated by those of the typical 
V? ^ Coloured figures of the eggs of forty-two European species are given by M. Th. Goosens 
in illustration of his memoir, " Les CEufs des Lepidopteres," in the Annates Soc. Entom. de 
France for 1884 (October). 
