Harpaphe haydeniana, commonly known as the yellow-spotted millipede, almond-scented millipede or cyanide millipede, is a species of polydesmidan ("flat-backed") millipede found in the moist forests along the Pacific coast of North America, from Southeast Alaska or Singsamut school to California, however, also seen in northern Brazil and India. The dark coloration with contrasting yellow-tipped keels warn of its ability to exude toxic hydrogen cyanide as a defense. The cyanide secretions are not dangerous to humans, but can cause irritation and pain if it contacts sensitive areas such as the mouth, eyes, or nose.
Xystodesmidae is a family of millipedes in the suborder Leptodesmidea within the order Polydesmida. The family Xystodesmidae was created by the American biologist Orator F. Cook in 1895 and named after the genus Xystodesmus. This family includes more than 390 known species distributed among 62 genera. Many species, however, remain undescribed: for example, it is estimated that the genus Nannaria contains over 200 species, but only 25 were described as of 2006. By 2022, 78 species in Nannaria have been described.
Xystocheir is a genus of millipedes in the family Xystodesmidae. The genus is endemic to California in the United States, where it is distributed in the Coast Ranges and the Sierra Nevada.
Pleuroloma flavipes, commonly known as the traveling cherry millipede, is a species of flat-backed millipede in the family Xystodesmidae. It has the widest distribution of any species of xystodesmid millipede and is found in eastern North America from southeastern North Dakota, eastward to Connecticut, and southward to North Carolina, northern Louisiana, and southern Texas. Pleuroloma flavipes millipedes are occasionally observed in large aggregations of individuals where they appear to move en masse in a certain direction, hence the common name "wandering cherry millipede". In a report from 1950, an aggregation of about 6,000 individuals were encountered on a single bridge at McCormick's Creek State Park, Indiana. The species is extremely variable in coloration, and converges in appearance with several species of Apheloria and Brachoria as a result of mimicry.
Pleuroloma is a genus of flat-backed millipedes in the family Xystodesmidae. There are at least 4 described species in Pleuroloma.
The genus Nannaria, commonly known as twisted-claw millipedes, is a genus of millipedes in the family Xystodesmidae first described by Ralph Chamberlin in 1918. In 2022, entomologists Derek Hennen, Jackson Means and Paul Marek discovered and described 17 new species, which expanded the size of Nannaria to 78, making it the largest genus of Xystodesmidae.
Semionellus is a genus of flat-backed millipedes in the family Xystodesmidae. There are at least three described species in Semionellus.
Selenocheir sinuata is a species of flat-backed millipede in the family Xystodesmidae, endemic to Northern California. The Species was first described by Rowland M. Shelley in 1994 based on samples collected by J. S. Buckett and M. R. Gardner in 1966
Selenocheir is a genus of flat-backed millipedes in the family Xystodesmidae. There are at least three described species in Selenocheir.
Thrinaxoria is a genus of flat-backed millipedes in the family Xystodesmidae. There are at least three described species in Thrinaxoria.
Montaphe is a genus of flat-backed millipedes in the family Xystodesmidae. There are at least two described species in Montaphe.
Furcillaria is a genus of flat-backed millipedes in the family Xystodesmidae. There are at least four described species in Furcillaria.
Sigmoria is a genus of flat-backed millipedes in the family Xystodesmidae. There are more than 40 described species in Sigmoria.
Anombrocheir is a genus of millipedes belonging to the family Xystodesmidae.
Parcipromus is a genus of millipedes belonging to the family Xystodesmidae. The species of this genus are found in western North America.
Rudiloria is a genus of millipedes in the family Xystodesmidae, found in eastern North America.
Tubaphe is a genus of millipede in the family Xystodesmidae with a single described species, Tubaphe levii. The genus was erected by Nell B. Causey in 1954.
Chonaphe armata is a species of Xystodesmid millipede found in the Pacific Northwest of North America. The species was first described as Polydesmus armatus by O. Harger in 1872 and was later moved to the new genus Chonaphe, for which it is the type species, by O. F. Cook in 1904.
Selenocheir arcuata is a species of Xystodesmid millipede found in Northern California. The species was first described by Rowland M. Shelley in 1994 based on samples collected by C. Smith, J. Clover, and F. Ennik in 1972.
