Marpissa muscosa Clerck, 1757 ♂
Meise, BRABANT ● Belgium
Description: Females reach about 8–11 mm length, males only 6–8 mm. Both sexes are colored grey to brown. The whole spider has a furry appearance and is flattened in shape.
Biology: The species builds a kind of nest under the bark of dead trees. Up to 100 of these nests can occur side by side.
Habitat: This species is often found on either tree trunks or fence posts. Here, it stay on a windows.
Distribution: Palaearctic. Widespread in northern Europe.
Wikipedia, Marpissa muscosa