We didn't go through the entire Insectarium, as we were most interested in the butterflies in the free special exhibit. I'm not too into bugs, so the other creepy-crawly things didn't interest me much.
The special exhibit, however, was wonderful. You walk into a huge room and follow a path, completing a circle of the room. There were thousands of butterflies just flying around, sitting on plants, and actually landing on people. I was told that the exhibit usually happens once a year, so if you are there during the right time, stop and see them. The only downside was that it was so crowded, you could barely move and had to travel at the crowds pace or risk being pushed.