
NIV.—THE 
tion is of course quite impossible without a female being 
transported in some way, and from observations made on 
a good many larvae of various ages, | am disposed to think 
that the migration of this. insect to new localities takes 
place at an early age, possibly soon after its emergence 
from the egg. On this account I think that the occurrence 
of the moth in both North and South Islands is of great 
interest, as it would seem to indicate the existence of some 
connection between the two islands, at a period not suffici- 
ently remote to have allowed any appreciable modification 
to take place in the insect’s structure and habits. At the 
same time, it should be borne in mind, that the protection 
afforded the larva by its case, and its ability to feed on so 
many different plants, may have rendered any modification 
unnecessary for the preservation of the species during re- 
cent times. The length of the full-grown caterpillar is 
about 1 inch. The head is dull yellow speckled with black. 
The first three segments are very hard, dark brown, with 
numerous white markings. The remaining segments are 
considerably thickened near the middle of the insect, rudi- 
mentary prolegs being present on the seventh, eighth, ninth, 
and tenth segments of the larva. The anal prolegs are very 
strong, and are furnished with numerous sharp hooklets, 
which retain the larva very firmly in its case. As the eater- 
pillar grows, it increases the length of its domicile from 
the anterior, causing it gradually to assume a more tubular 
form, tapering towards the posterior aperture, which is 
enlarged from time to time. The outside is covered with 
numerous fragmentary leaves and twigs of various sizes, 
placed longitudinally on the case; and, frequently, near the 
anterior aperture, the materials, owing to their recent selec- 
tion, are fresh and green. In rare cases moss or even stones 
are attached. The interior is ined with soft, smooth silk 
of a light brown colour, the thickness of the whole fabrie 
being about the same as that of an ordinary kid glove, and 
so strong that it is impossible to tear it, or indeed to cut 
it, except with sharp instruments. The size of the case, 
when the caterpillar is mature, varies considerably, ranging 
from 24 to 3 inches or more in length, and about 4 inch in 
diameter, the widest portion being a little behind the ante- 
rior aperture. 
During the day the larva closes the entrance, and spins 
a loop of very strong silk over a twig, the ends being joined 
to the upper edges of the ease on each side; in this way it 
hangs suspended, the caterpillar lying snugly within. I 
have often known a larva to remain thus for over three 
weeks without moving, and afterwards resume feeding as 
before; this probably occurs whilst the inmate is engaged 
in changing its skin. At night the larvae may be seen 
busily engaged: they project the head and first four seg- 
ments of the body beyond the case, and walk about with 
considerable rapidity, often lowering themselves by means 
of silken threads; the only locomotive organs are, of course, 
their strong thoracic legs, which appear to easily fulfil their 
double function of moving both larva and ease. If dis- 
turbed, these insects at once retreat into their cases, closing 
PSYCHIDAE. 213 
the anterior aperture with a silken cord, which is kept in 
readiness for the purpose, and pulled from the inside by 
the retreating larva. This operation is most rapidly per- 
formed, as the upper edges of the case are flexible, and thus 
fold closely together, completely obstructing the entrance. 
When full-grown, this caterpillar fastens its case to a 
branch with a loop of strong silk, which is drawn very 
tight, preventing the case from swinging when the plant is 
moved by the wind, and also rendering the insect’s habita- 
tion more inconspicuous, by causing it to resemble a broken 
twig. The anterior aperture is completely closed, the loose 
edges being drawn together and fastened like a bag. The 
posterior end of the case is twisted up for some little dis- 
tanee above the extremity, thus completely closing the 
opening there situated. It is lined inside with a layer of 
very soft silk spun loosely over the sides, and partly filling 
up each end. In the centre of this the pupa lies with its 
head towards the lower portion of the case, the old larval 
skin being thrust backwards amongst the loose silk above 
the insect. 
The male and female pupae may very easily be dis- 
tinguished. The male pupa is rather attenuated, and has 
all the organs of the future moth plainly indicated on the 
integument, as is usual with Lepidopterous pupae. The 
female pupa, on the contrary, is merely a chain of segments, 
with a few faint indications of rudimentary organs on the 
anterior extremity. It is, moreover, much larger than the 
male pupa. 
The insect remains in this condition during the late 
winter months. About September the male pupa works its 
way down to the lower end of the case, forces open the old 
aperture there situated, and projects the head and thorax, 
the pupa being secured from falling by the spines on its 
posterior segments, which retain a firm hold in the silk. Its 
anterior portion then breaks open, and the moth makes its 
escape, clinging to the outside of its old habitation, and 
drying its wings. 
The male insect must be on the wing from September 
till December, but is very rarely observed, although strag- 
glers have been detected during the winter months. In 
captivity it is extremely active when first emerged. Indeed 
the male moth is so vivacious, that it often happens, owing 
to the emergence usually taking place very early in the 
morning, specimens are more or less injured by their efforts 
to escape, before they are discovered in the breeding cage. 
This restless energy of the male is no doubt essential to the 
insect’s well-being, as the females, hidden away in their 
eases and incapable of any movement, must of necessity be 
very hard to discover. The power of locomotion lost in 
the one sex is thus doubled in the other. Considering the 
protection afforded this insect by the case, which it inhabits 
during its preparatory stages, its enormous mortality from 
the attacks of a parasitic dipteron (Phorocera marginata) 
is very remarkable. In this connection the following 
analysis of 38 eases, gathered at random, may be of 
interest :— 

