Larva (critter)

Larvae are level 1 critters found mainly in the Ghostlands and Naxxramas.

Pet Journal
''This new arrival to Azeroth was spawned a short time ago. It seeks to thrive while awaiting its next phase of evolution.''

Achievements
Killing one of these is required for Pest Control.

Note
Don't be discouraged by the abundance of Maggots in the Dead Scar - Larva definitely spawn in the Ghostlands! However there seems to be not a specific area where they can be found. Probably the fastest method for Larva spotting is riding around the zone while hitting a key that is bound to a targetting macro ("/tar Larva").

Other players also recommend rather than just search for a wild Larva, to look out for wild pets that are level 5 and higher. These will always have a second pet join the battle, which can include Larva. Make sure you use a team that can survive battling two pets, but will not kill the one you want outright by accident.