6 BUTTERFLIES OF MAINE. 
mandibles attached one on each side of the mouth, which 
work laterally. Beneath these are the mazille or lesser jaws 
placed in a similar manner, which with the mandibles form 
the sides of the mouth. The mallee are used to hold the 
food rather than for chewing, and are furnished with a pair 
of jointed organs called the maxillary palpi which are used 
as organs of touch. 
Below the mazille is situated another plate called the 
labium or lower lip which forms the lower boundary of the 
mouth. This is also furnished with a pair of jointed organs 
called the labial palpi. There is also a soft, conical, horny 
tube called the spinneret, on the soft membrane of the 
labium. It is the common excretory duct of those glands 
which secrete the silken threads by means of which the 
chrysalis is suspended and leaves are drawn together by those 
species which conceal themselves, and also the cocoons are 
formed by those species which transform in them. The 
antenne, though but slightly developed, are situated a little 
above the base of the mandibles on each side of the clypeus, 
and are of a conical form and jointed. There are six very 
minute simple eyes at a little distance from each other, near 
the base of the mandibles. 
EXTERNAL ANATOMY OF THE PUPA. 
The pupa state in butterflies is a very peculiar and char- 
acteristic period of their existence. Externally a perfect 
standstill appears in the process of development, for the 
pupa is quiet and does not take the least nourishment ; 
but internally, great changes are in progress. 
Those pupae which hang freely from one end, or are 
supported by a loop of silken threads, are called naked pupae, 
while those which rest in cases of silk spun by the larvee just 
before transforming into pup, are called incased pupae, 
and their cases are called cocoons. The outside covering of 
a pupa is of a fine, horny texture, and shows the parts of 
the future insect more or less plainly. The pupa shows the 
