Attached to the beautiful Jardin Bontanique is the wonderfully interesting Insectarium. This museum is NOT for everyone, especially if viewing giant African beetles isn't your thing. If you can suspend your internal nausea factor, this museum is a pretty fascinating look at the bazillion species of insects that populate our planet.
There's a bit of a double edged sword here: if live bugs make you squirm, then the Insectarium might be good for you because most of the bugs (esp. the seriously gross ones) are dead and mounted. This may be disappointing for the bug enthusiast who wants to see more live samples. I find the live bees the most interesting because you can watch the whole hive operating.
The facilities are large, though not sprawling. Little kids may get bored easily, but bigger kids will like this museum. Admission can be bundled in at a slight discount when paired with other Jardin Botanique attractions.