Order Siphonophorida (3 families) - gonopods comprised of caudal legs on segment 7 and anterior on segment 8; body relatively narrow, tergites without"paranota"; head prolonged into a variable "beak." Includes the millipedes with the most legs/feet. Occurrence: North, Central and South America, Caribbean, South Africa and southeast Asia. New World occurrence: central California, Arizona and Texas to southern Brazil and Peru; Greater and Lesser Antilles.

Figure 13. (left) Illacme plenipes Cook and Loomis, the world's "leggiest" animal, from San Benito County, California, left antenna missing. Photo by J. Page.

Order Stemmiulida (1 family) - gonopods comprised of anterior legs on segment 7, posterior legs on segment 7 reduced to nonfunctional remnants; body subcylindrical, tapering caudad, head with a pair of large ocelli; caudal end with spinnerets. Occurrence: Mexico to Panama, Greater and Lesser Antilles, central Africa, India, and New Guinea.

Figure 14. (Right) Head and anterior segments of Prostemmiulus sp. from Puerto Rico. Drawing by R.G. Kuhler.

Order Chordeumatida (about 32 families) - gonopods comprised of both leg pairs on segment 7; body subcylindrical, tapering caudal, toward tapered end, occasionally with paranota, 26-32 segments, caudal end with spinnerets. Occurrence: North and Central America, Chile, Europe, north Africa, Madagascar, Asia and Himalayas northward, Indonesia, Australia, and New Zealand. New World occurrence: Newfoundland, Labrador, northern British Columbia, and Alberta, to Florida, the Gulf Coast, and Panama; Chile.

Figure 15. (Left) Scoterpes copei (Packard), a cave chordeumatid from Kentucky.

Order Callipodida (4 families) - gonopods comprised of anterior legs on segment 7; body generally cylindrical and frequently ornamented with ridges and crests, 40-60 segments, caudal end with spinnerets. Occurrence: North America, Mediterranean region of Europe, Asia Minor to Pakistan, China and Vietnam. North American occurrence: southern Minnesota, Michigan, and New York to south Florida, the Gulf Coast, and northeastern Mexico; San Francisco Bay area of California, central Nevada, and Utah to southern Baja California and Sinaloa, Mexico.

Figure 16. (Right) Abacion magnum (Loomis) from North Carolina. The gonopods are shown just behind the head in the ventral view of a male. Scale in cm. Photo by T. Owens.

Order Julida (16 families) - gonopods comprised of both leg pairs on segment 7; body generally cylindrical, with conspicuous grooves or striae in two families, 30-90 segments; mostly small to moderate-size millipedes but with the longest species in North America (about 12 cm [6 1/2 inches] long). Occurrence: North America, northern Central America, Europe, Asia from Himalayas northward, and southeast Asia. A number of species have been widely introduced through human commerce, a few of which now occur globally. North American occurrence: central Alaska and northern Canada (the Yukon to northern Quebec) to southern Florida and Guatemala.

Figure 17. (Left) Cylindroiulus boleti (Koch), from Hungary. Photo by Z. Korsos.

Order Spirobolida (10 families) - gonopods comprised of both leg pairs on segment 7; body generally smooth and cylindrical, 35-60 segments; mostly moderate-size to large, robust millipedes. Occurrence: North Central and South America, Caribbean, sub-Saharan Africa, eastern and southeastern Asia to Australia. Several species have been widely introduced by human commerce, two of which now occur on tropical islands throughout the world. New World occurrence: southern Quebec, southern Michigan/Wisconsin, and Washington to southern Florida, the Gulf Coast, and southern Brazil and Peru; Greater and Lesser Antilles.

Figure 18. (Right) Four specimens of Narceus americanus (Beauvois).