This study provides the first photo-documentation of some of the sanguivorous terrestrial leeches of Madagascar, including the characterization of the male and female reproductive systems that were previously considered to be “monotonous” in land leeches. Three species of Malagabdella are redescribed and one new haemadipsoid species, Malagabdella niarchosorum, n.sp., is described. M. niarchosorum, n.sp. is the second species described from Madagascar that possesses four complete annuli between the gonopores. The only other Malagasy leech with these same characteristics, Malagabdella dussumieri (Blanchard, 1917), has an unknown type locality, and the examination of the type specimen reveals characteristics suggesting that this leech was not from Madagascar. A revised and restricted provisional key for the Malagabdellinae is provided.