Phalangium is a genus of harvestmen, that occurs mostly in the Old World. The best known species is Phalangium opilio, which is so common in many temperate regions that it is simply called "harvestman".

Source Of the 35 species listed above, 6 are valid [P. ligusticum, P. opilio (originally described in 1758, not 1761), P. punctipes, P. riedeli, P. savignyi (originally described by Audouin, not Savigny) & P. targionii], 3 belong to different genera of the opiliones, 4 belong to different arachnid orders, 2 are species inquirenda and 20 are nomina dubia. The type species is P. opilio, not P. iberica [which has been synonymised with Metaphalangium cirtanum (CL Koch, 1839)], as designated by Latreille in 1810. In addition to the 6 valid names from the above list, the genus Bactrophalangium (with its 2 species) has been synonymized into Phalangium, 8 species have been described since 2005 and one species described in 1953 is missing from the above list, making a total of 17 species currently recognized as valid.