You can take the mission from any Dr. Medford, but depending on your level you have to kill a specific Mother Skitter.
1x Trick or Treat Bag
|Chain||From Beneath You|
|Sector||Grand Canyon Province|
Here, take this. It won't do me much good but you might have some fun with it. We'll keep looking at the bug situation, but from what I can tell, the answer lies south of Epsilon...