Actually her character profile lists her name as "Etanity Larva", which also matches her Japanese name エタニティラルバ. The in-game name is probably a slip-up on ZUN's part.
Either way, I'm questioning if it's worth renaming the tag to "etanity_larva" or just leaving it until the full release corrects either the game or omake.
I also propose calling her "Eternity Larva" as I presume that's what Zun's going for. We also didn't call Flandre "Flandle" or Maribel "Marryberry" (that's a whole nother can of worms).
Her profile mentions she emits a bad smell from her antennae when threatened. That's because they're actually an osmeterium, a pair of fleshy "horns" swallowtail larvae stick out when disturbed, emitting a foul odor that deters predators.