Illacme is a genus of millipedes in the family Siphonorhinidae.[1] It includes two species.[2] Illacme plenipes was first described in 1928 from San Benito County, California, and rediscovered in 2005. In 2016, Illacme tobini was described based on a single male specimen collected in 2006 from Lange Cave, in Sequoia National Park, 240 km (150 mi) east of the known habitat for I. plenipes.[3]