Another Pirata sp with egg sac and 'eyespots' 22/07/2014, same habitat
For comparison, a female nursery web spider carrying her egg sac with her chelicerae.
24/05/2014A frontal view of the same male showing his enlarge palps:
Why would this be beneficial to this spider? What follows is only speculation, but apparently, wolf pirate spiders live in retreats in moss at the shore of ponds, and females carrying egg sacs often expose the egg sac to the sun at the retreat entrance, while the female remains inside. This could put the female in danger of predation, as she would be less able to detect danger, so the eyespots could afford some protection to the mother and its offspring to be, but I am not aware of any research into the evolution of these eyespots.
With thanks to Catherine Scott (@cataranea) for discussing this on twitter before I wrote the post.