Lepidoptera
are Holometabolous insects (insects which have larvae that look nothing
like the adults/imagos and having a complete metamorphosis with a pupal
stage). They possess two pairs of membraneous wings with few cross
veins, (though these may be absent in the females of some moths). The mandibles
are present in the larvae but nearly always absent in the imagos/adults
in whom the principal mouth parts are a sucking tube or proboscis formed
from the maxillae which is held curled up in a spiral under the head when
not in use (in a number of species of Moths the mouthparts are all degenerate
in the imagos and these do not feed at all. The antennae are variable in
length and may be quite complicated in some male moths The imagos have two
large compound eyes with as many as 6 000 omatidium and two ocelli, while
the larva often have simple ocelli. The wings and body of the imagos are
covered in scales and the
body of the larva are generally covered in hairs (though these may be very
fine and short). The salivary glands of the larvae have become modified
to form the silk glands. The larvae are 'eruciform' (which means they look
like a caterpillar) and in most cases
have 13 body segments with three pairs of jointed legs on the first three
segments, (which are roughly equivalent to a thorax in the imago). Segments
3 to 6 of the abdomen (6,7,8,9 counting back from the head with the head
as 0) each have a pair of unjointed pro- or false-legs, these end in a contractile
pad surrounded by a ring of minute hooks; there is also a pair of unjointed
claspers on the final segment.
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