The little known Robertus insignis O. P.-Cambr. is described on material from Knisa mire, Prov. of Oland, Sweden, where it is of rare occurrence. The species belongs to the Robertus-group in which females have a separate posterior plate and a divided receptaculum, and males a hook-shaped embolus. The species seems to show affinitiy to R. lyrifer Holm and R. pumilis (Emerton).