This is an interesting derivative of the Open Terrarium technique.  Because last instar indra swallowtail caterpillars can wander off the plant to rest, this setup makes it much easier for them to return to the plant to feed. 

There are holes drilled in the base of this setup where the neck of the water bottles enter allowing for the stalks of the host to be right at the bottom of the cage allowing for easy exit and return for wary indra caterpillars.