For those that are doing this quest and any others that require killing Jungle Crawler Workers or Jungle Crawler Soldiers they can be found on New Trismus in the Sslanis Jungle north of the town of Sslanis. If traveling down from the north exit Sslanis to the west and soon after leaving the town you will come to a small trail on the right side of the road. There are some skeletons standing at this juncture. Take the path and follow it up till you come to another path connecting from the left. This path will lead to the crawlers.

However there is a named skeleton that patrols the paths and is deadly to the younger hunters. To avoid him turn off to the left before arriving at the path that comes in from the left. As you enter the jungle to the left you will come across a shrine like spot and a smelter a little further in. There are tin & copper nodes about as well. Going just beyond the smelter you will come to a depression like area where you can safely pull the crawlers from and where the named skeleton will not aggro you. The spot is approx. 19822/22100 on the game map.

From this spot you should be able to safely pull the crawlers from the path without being aggroed by more crawlers or the skeleton. If you get into trouble you can retreat uphill to the cliff face behind you. I have discovered if you go back just beyond the lip the mobs will turn around and run back to their previous spot. I'm guessing the zone line runs through there and that is what turns them around.

I hope this description helps