female D. saccatus with male left pedipalp. Mosaicism is quite rare in spiders
Drassodes is a spidergenus in the family Gnaphosidae. They can reach a length of about 20mm; the brownish spiders live under rocks or bark in mostly dry habitats.
References
Platnick, Norman I. (2007): The world spider catalog, version 8.0. American Museum of Natural History.