Caterpillars walk by lifting and compressing the body
between the last two pairs of legs, then moving the last
pair of legs forward a bit,
then they lift the next segment and move the penultimate
pair of legs forward,
then the next pair , and so on.
There is a considerable distance between the last pair of
true legs
and the first pair of
prolegs,
so that that step in the sequence is usually longer,
giving Caterpillars more mobility than might be imagined,
especially if some pairs of
prolegs are not present,
as in some members of the families
GEOMETRIDAE and
NOCTUIDAE.
