>Mike Petro also has something on his site about it.

See http://www.pu-erh.net/static.php?StaticID=13


As with any agricultural product, insect infestation is not uncommon.
Puerh is often warehoused for years which dramatically increases the
probability that a few critters will set up shop in there.

Quite frankly, in all likelihood the infestation occurred long before
your particular vendor acquired the Puerh. While the vendor certainly
should give you full credit for the cake if you find all of this
distasteful, it is probably not the vendors fault.

As Mydnight alluded to, in Asia the presence of insects is not seen
with the same repulsion as it is in the western world. Many Asians see
it as a good thing. A "rope" of insect droppings is sometimes found in
between the cakes and the leaf wrapping on tongs of really old cakes.
This "rope" is highly valued, the longer the rope the more it is
prized.

So take all of this into consideration before you beat up your vendor
too badly.....

--
Mike Petro
http://www.pu-erh.net