The Ghost Spider mounts of Geisterdamen Eotain and Shurdlu, respectively. They're first way out in the boonies, as Agatha and the gallant but ill-starred Lars are rehearsing their lines for a Heterodyne Play, but we don't know their names at this time. The "spider riders" (and the ridden spiders) go silent for literally years' worth of episodes, but they reappear in Paris at just about the same time as our heroine, coincidentally enough. (Right.)
Unfortunately (at least for the Geisterdamen, if not for Agatha and minions), Bwoosee takes what appears to be a fatal blow from a piece of hardware, much to the sorrow (not to mention rage) of her rider. It is as a result of this little encounter that we learn the spiders' names, but somehow, that's probably not much consolation for the spider riders. For the moment, at least, we're therefore down to one named ghost spider. This is probably just as well.