Yellow-Spotted Millipede

The yellow-spotted millipede, Harpaphe haydeniana, is a flat-backed millipede of the family Xystodesmidae found in moist forests along the Pacific coast of North America from Southeast Alaska to California and east to the Sierra Nevada. Adults reach four to five centimeters in length, with black to olive-green bodies marked along the sides with patches of yellow across roughly twenty segments and thirty to thirty-one pairs of legs. It defends itself by exuding toxic hydrogen cyanide, and its dark coloring with yellow-tipped keels functions as a warning to predators, though the secretion is only mildly irritating to humans.