Explanation of Names
From Greek polys (πολυς)- "many, very" + xenos (ξενος)- "stranger, foreigner" or "strange, foreign". In ancient times it was used to describe someone who was hospitable to strangers, but it could also be translated as "very strange"
Known North American occurrences from (1)
P. fasciculatus: "Coastal Plain" - from MD to TX, north to IL
P. lagurus: MA, NJ, NY, MI, IL, MT, WA, CO, AZ. Widespread in Western Europe.
P. pugetensis: OR, WA, BC?
P. anacapensis: Channel Islands off southern CA.
Their typical habitats are generally described as litter and bark, also commonly collected from rocks and old walls (Wright & Westh 2006)
Quinn (2000) collected over 900 spmns (Polyxenus
sp.) throughout his sampling period of March-August in central Texas. They were fairly evenly present on live oak, cedar elm and juniper, but less than 20 were found on red oak. (2)
They are diurnally active, feeding on algal films and lichens, often in warm and dry conditions and direct sunlight. (Wright & Westh 2006)
The millipede Polyxenus fasciculatus defends itself against ants by use of a pair of bristle tufts at its rear. When attacked, it wipes the tufts against the ants, thereby causing these to become encumbered by bristles that detach from the tufts. Ants contaminated with bristles desist from their assault. The bristles have grappling hooks at the tip by which they lock onto setae of the ants and barbs along their length by which they interlink. In attempting to rid themselves of bristles, ants may succeed only in further entangling themselves by causing the bristles to become enmeshed. Ants heavily contaminated may remain entangled and die. Most millipedes have chemical defenses; polyxenids, instead, have a mechanical weapon. (Eisner et al. 1996)
Chamberlin, R.V. 1922. A new milliped of the genus Polyxenus from the Florida Keys. Entomological News, 33 (6): 165.
Eisner, T., M. Eisner and M. Deyrup. 1996. Millipede defense: use of detachable bristles to entangle ants. Proceedings of the National Academy of Sciences 93: 10848–10851. Full PDF
Kincaid, T. 1898. A new species of Polyxenus. Entomological News, 9: 192-193.
Pierce, 1940. A rare myriapod from Anacapa Island, compared with two Texas species. Bull. Southern California Acad. Sci., 39 (2): 158-171.
Say, T. 1821. Description of the Myriapodae of the United States. Journal Acad. Nat. Sci. Philadelphia, 2: 102-114.
Wright, J.C., and Westh, P. 2006. Water vapour absorption in the penicillate millipede Polyxenus lagurus
(Diplopoda: Penicillata: Polyxenida): microcalorimetric analysis of uptake kinetics. Journal of Experimental Biology 209: 2486-2494. Full Text