When the bug zapper is in your inventory, any a skittish scarab that you approach will automatically herd toward the tarantula field ( -1062, -115, -589 ) /waypoint -1061.92, -114.92, -589.22. Tarantulas kill scarabs on sight, with a huge aggro radius.
Herd a skittish scarab to its death.
You must stay fairly close to the scarab, to keep it moving toward the tarantula field. They follow a set path, heading directly towards the tarantula field. There is no way to divert them from this path. Once there they will circle the group of boulders at the center. ( -1039, -106, 701 ) /waypoint -1039, -106, 701
Skittish scarabs spawn throughout the flat area north of Xilla (between her and the chimney). You can spot them from a distance because they fly non-stop.
There are a max of 4 skittish scarabs. If no one has been hunting them when you come along, all 4 will be up. They do NOT share spawn points with the normal dune scarabs.
Retrieve the dead scarab's carapace. You have to stay almost next to the scarab to get the carapace.
When a tarantula kills a skittish scarab that you herded, a carapace will appear on the ground. Right-click the carapace to pick it up. (you can attack the scarab's as long as the tarantula starts the fight and kills it. this makes it much faster)
Note: You can pickup carapaces from a long distance away. There is no need to be attacked by tarantulas. They normally walk away after killing a scarab.(But you have to be fairly near to the scarab when it dies or it will not drop the carapace).
Be sure not to get more than one scarab at a time. It is possible that the resulting shells would be non-lootable.