Phalangium opilio

Phalangium opilio, commonly called the common harvestman, brown harvestman or daddy longlegs, is a species of harvestman in the family Phalangiidae, within the arachnid order Opiliones and the suborder Eupnoi, described by Carl Linnaeus in 1758. Adults measure 3.5 to 9 millimeters in body length, with long, slender legs and a compact body; males have noticeably larger pedipalps and chelicerae with prominent horn like outgrowths that distinguish them from females, while both sexes are marked light brown and grey, often with a light cream underside. It has four pairs of legs, with the second pair used mainly for sensing rather than walking. The species has a mostly Holarctic distribution and is the most widespread harvestman species in the world, native across Europe, Asia and Asia Minor, and introduced to North America, North Africa and New Zealand, where it occupies a wide range of open habitats including meadows, bogs and forests and thrives in human modified environments. It acts as both a predator and a scavenger, giving it value for agricultural pest control.