Gonopod morphology is the predominant means of determining species among millipedes: the complex structures differ much between species but very little within a species.
The millipede's most obvious feature is its large number of legs.
Light is emitted from the exoskeleton of the millipede continuously, with peak wavelength of 495 nm (the light intensifies when the millipede is handled).
Because they lack a waxy cuticle, millipedes are susceptible to water loss and must spend most of their time in moist or humid environments.
They have been recorded as eating pill millipedes, snails, other arthropods and soft-bodied invertebrates such as earthworms.
Some are predators or parasites of earthworms, snails, spiders, centipedes, millipedes and insect eggs, larvae and pupae.
The millipede has glands that produce hydrogen cyanide to protect it from predators, a fact advertised by its aposematic color.
Apart from the rolling-up behavior of giant pill millipedes, camouflage may be an important defense mechanism against predators that hunt by sight, such as birds.
