We have rearranged the configuration of the hive so it is easier to keep the ants out. We've also added a new super. A super is a box that beekeepers use for honey only, no larvae. There is a mesh called a queen excluder between the super (on top) and the box below. The mesh has holes big enough for worker bees, but not for the queen since she is larger. I am adding 3 empty frames to that box tomorrow. Those will probably soon be filled with honey.
Here's a picture from flickr of a beekeeper with a queen excluder.
The bees are still suffering from varroa mites. Outside the hive can be spotted a number of dead bees that have been dragged out of the hive. I saw two bees with wing damage from the varroas. Here's an extreme example from flickr.