Xystodesmid Millipedes

image of Xystodesmid Millipede crawling on a forest floor
Scientific Name
8 tribes, with about 23 genera, in North America north of Mexico
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.

Other Common Names
Flat-Backed Millipedes
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Similar Species
About Land Invertebrates in Missouri
Invertebrates are animals without backbones, including earthworms, slugs, snails, and arthropods. Arthropods—invertebrates with “jointed legs” — are a group of invertebrates that includes crayfish, shrimp, millipedes, centipedes, mites, spiders, and insects. There may be as many as 10 million species of insects alive on earth today, and they probably constitute more than 90 percent all animal species.