Ptinus fur, the white marked spider beetle, is a species of spider beetle in the genus Ptinus (family Ptinidae), with a nearly cosmopolitan distribution.^[1]

Wikispecies has information related to Ptinus fur.

Adults are morphologically similar to other spider beetle species, notably the hairy spider beetle (Ptinus villiger).^[2] It is red-brown with yellow hairs, and measures 2.0–4.3 millimetres (0.08–0.17 in) in length. The prothorax is densely covered with pale hairs, while the elytra bear some patches of white scales.^[1]

It is a pest of stored foods,^[2] with a worldwide distribution, where it may be identified by leaving webbed, granular materials on the stored products.^[2] Ptinus fur adults feed on dried and decaying animal and vegetable material.^[2][3] It has also been identified as a pest in museums, damaging stored collections.^[3]

It has been found in the nests of birds, notably the Sand Martin.^[4]

The optimum temperature for rapid development of Ptinus fur is about 23 °C, at which temperature it completes its development in a mean period of 132 days.^[5] Larvae of P. fur normally moult three times at 23°Cm but some have an extra moult.^[5]

Well-defined diapause as mature larvae in cocoons occurs at low temperatures in some individuals of Ptinus fur: at 23 °C this lasts about 220 days after normal larvae have pupated; at 20 °C the period lasts about 280 days.^[5]

Adult beetles live for several months.^[5]