274 STATES OF INSECTS. (Pupa.) 
which are without elytra, to make their way out of such 
situations, without irreparable injury to their delicate 
wings. Many of these, therefore, while still within the 
hard case of the pupa, have the precaution, a few days 
previously to their exclusion, to force themselves up to 
the surface of the earth, or, when they reside in the in- 
terior of trees, to the entrance of their hole. ‘This is ef- 
fected by a successive wriggling of the abdominal seg- 
ments, which in several species of the Coleoptera, Lepi- 
doptera, and Diptera orders, for this purpose, as has 
been more than once observed?, are furnished with 
sharp points (adminicula), admitting a progressive, but 
not a retrograde motion. The puparia of the great goat- 
moth (Cossus ligniperda) may be often seen projecting 
from orifices in willow-trees; and those of the common 
crane-fly (Z%pula oleracea) from the surface of the earth, 
to which they have thus made their way from a depth of 
several inches. 
In all the preceding instances the exclusion of the per- 
fect insect is complete, as soon as it has withdrawn itself 
from the puparium. But to a very large number, even 
after this is effected, the arduous task still remains of 
piercing the cocoons of leaves, of thick silk, of tough gum, 
or even of wood, in which the pupee are incased. We 
can readily conceive how the strong jaws of coleopterous 
and hymenopterous species may be employed to release 
them from their confinement. But what instruments can 
be used for this purpose by moths in a state of great de- 
bility, whose mouth has nothing like jaws —merely a soft 
membranous proboscis? How shall the silkworm-moth 
(Bombyx Mor7) force its way through the close texture 
* See above, p. 254—. and Vor. II. p. 297—. 
