A Work Bug was a type of workpod, a small, three-person space vessel designed for heavy-duty industrial operations. Larger than Starfleet's standard one-person Work Bees, they allowed for a greater range of tasks.
The USS da Vinci received two of the new Work Bugs in 2376, prior to their assignment to Tenber VII. Both Work Bugs were lost during efforts to recover the Wildfire device from the atmosphere of Galvan VI. (SCE eBooks: Wildfire, Book 1, Wildfire, Book 2)