Xystodesmid Millipedes

8 tribes, with about 23 genera, in North America north of Mexico


image of Xystodesmid Millipede crawling on a forest floor
Millipedes with bright colors, such as this member of the family Xystodesmidae, are more likely to secrete foul or toxic substances in defense. The bright coloration is a warning to predators.
Donna Brunet
Other Common Name
Flat-Backed Millipedes

Xystodesmidae (a family of flat-backed millipedes) in the class Diplopoda (millipedes)


Millipedes in family Xystodesmidae (pronounced ZISS-toe-DES-mih-dee) often have bright colors (yellow, red, or orange, plus black or dark brown) that serve as a warning to potential predators that they may secrete foul or toxic substances.

To defend themselves, several species secrete substances containing cyanide, so it is important to wash your hands thoroughly after handling these animals. It is best not to let children or pets touch them.

Like other millipedes, xystodesmids are peaceful scavengers and are not aggressive to people.

Xystodesmidae is just one of several families of flat-backed millipedes (order Polydesmida), which are named because their body segments typically flare out at the bottom edge, making them look flattened, instead of having the cylindrical look most other millipedes have.

At least two common and nearly identical species may be found in Missouri; both are widespread in the eastern United States:

  • Apheloria virginiensis (Virginia apheloria)
  • Pleuroloma flavipes (yellow-legged pleuroloma)

Learn more about these and other millipedes in their group entry.


Photo of xystodesmid millipede crawling on soil at the base of a bunch of grasses.
Xystodesmid Millipede in Prairie
Millipedes are common, though they are not commonly seen or noticed. This xystodesmid millipede was photographed at Friendly Prairie Conservation Area in Pettis County.