leg - one of the six chief organs of locomotion of an insect, arising from the segments of the thorax, and which are made up of four main portions, the
coxa,
femur,
tibia, and
tarsus. (The second segment, the
trochanter, is very short.) Sometimes the tarsus has an elongated first section, the
metatarsus.
Some insect
larvae, especially
caterpillars, have fleshy
prolegs, often in addition to six true legs. Photos/diagrams showing prolegs and true legs in a caterpillar: