What is "siphoniulus"

Siphoniulus is a poorly known genus of millipede containing only two species: S. alba from Indonesia, and S. neotropicus from Mexico and Guatemala. These two species are the only members of the family Siphoniulidae and order Siphoniulida, making Siphoniulida the smallest millipede order. Few specimens are known, and their classification is contentious, although most recent studies place them as basal members of the Helminthomorpha ("worm-like millipedes").