Opilio canestrinii, commonly called Canestrini's harvestman is a species of harvestman arachnid.
Males reach a body length up to 6 mm, females up to 8 mm. While males are yellowish brown to reddish, females are lighter. Males have dark legs, but yellow coxae and "knees"; the legs of females show alternating light and dark rings. The backs of females sport a dark, saddle-like pattern with a light longitudinal stripe in the middle. Adults can be found from June to December. Bellmann, Heiko (1997): Kosmos-Atlas Spinnentiere Europas. Kosmos. (in German)
Opilio canestrinii probably originates from Italy, but has invaded Central Europe since the late 1970s, and has since almost everywhere replaced the similar O. parietinus. It is most often found on house walls.
References
Further reading Joel Hallan's Biology Catalog: Phalangiidae