Psycho-lettes

A gang of female bikers that call themselves the Psycho-lettes (because their bike models are Mobylettes) ride across the South of Spain killing men and cutting their manhoods off, which they keep as trophys. Captain Loperena of the Civil Guard and his sidekick go after them. The Psycho-lettes make a potion out of men's fluids, drink it, and are killed by a green octopus-like creature. Loperena finds the corpses and attribues the capture of the gang to himself.