Hello! Thanks for posting this for people! There is, however, already a thread about it here:
http://forums.wow-petopia.com/viewtopic ... 7&start=40
The details (I just double-checked myself to be sure it's accurate):
Cinderweb Broodling 1 are not tameable. They spawn from a Hyjal Scout who periodically wanders up into the Widow's Clutch, says "I don't feel so good," asks for help and falls over. The spiders spawn, and despawn 30 seconds or so later.
Cinderweb Broodling 2 are tameable. These spawn and quickly patrol through the Widow's Clutch to the nest area near the center, despawning shortly after.
In size, group size, color, model, level and HP, these spiders appear identical. Their NPC IDs and tameability are the only differences.
The tameable ones--the ones on this page, with the NPC ID 53753 (note this if you use NPC Scan)--(edited out)-- We now have it on good authority that they simply (like the Clutchkeepers in the area) have a 50% chance per day to spawn. "If you don't see them, come back the next day."
This means there are two tameable green lava spiders right now, these and Kirix, both unreliable spawns (considering our current knowledge)--and one "red herring."