I see what you are saying.
There is a line item for the spider but the spider name is blank.
I would suspect you have something hosed in the agents listing causing guests to appear as spiders but...
Maybe repost what you have here.
Another quick way to find the agent setting is.
As a admin when viewing the whos online.
You can select the I icon and view the agent listing for the unknowns.
That can help narrow down the settings to search for.
