Question from C.G.: What is the different between a millipede and a centipede? How can I tell which is which?
Answer from Coastalfields:
It can be confusing to learn which is which without seeing a picture... for this reason we have included several. These "bugs," besides having such similar names, have a few other common characteristics that makes identifying them challenging.
Neither are insects, but are distant "cousins" to insects; insects, millipedes, and centipedes are all Antropods (as are lobsters, spiders, mites, and many other creatures). Millipedes and centipedes both belong to the Superclass Myriapoda. Both are long and thin with many legs. Both live underground and among rotting leaves and wood, and are typically seen when digging in the garden.
Despite their similarities though, they are actually quite different in appearance. As you may guess from the names, centipedes ("hundred feet") have less legs than millipedes ("thousand feet"). Unfortunately, this is only useful if you know what they both look like but can't decide which is which. Otherwise, how would you know which has more when you haven't seen the other?
Millipedes (Class Diplopoda) do not actually have one thousand legs, they just seem to (depending on the species and age, they can have between 94 and 750 legs). They have one pair of legs on the front three segments of their body, and two pairs of legs per segment on the rest of their body. When they walk, their tiny legs move so fast that they almost appear to have none at all!
Their bodies are long and very thin, and of a dark brown color. Their bodies seem very smooth, with many segments at regular intervals. Every time they molt, they add a new segment with more legs! They have an obvious head and tail, as they have antennae on their head and their tail end is smooth.
Most millipedes eat decaying matter, such as rotting leaves. A few are carnivorous. When they are frightened, they curl up into a tight spiral. They will not bite when handled, but their bodies do secrete a defensive poisonous substance (for some species, this substance contains cyanide).
Centipedes (Class Chilopoda) do not actually have one hundred legs, they just seem to (depending on the species, they can have between 15 and 177 legs, but always an odd number). They have one pair of legs per body segment. Centipedes are also long (usually a little bigger than millipedes), but not very thin; this makes them look much larger than a millipede.
Their legs are not tiny (as the millipedes are), and project out to the side. They are light to medium brown in color. Their bodies are not as smooth and streamlined as a millipede, and are somewhat flattened in appearance; they are segmented at irregular intervals. Their heads also have antennae, but their tail ends are pointed. Centipedes do not curl up when frightened.
Centipedes are predatory - they hunt worms and insects which they kill with their venomous claws. They may bite people too, if handled, but are not venomous enough to cause serious injury.