From Nookipedia, the Animal Crossing wiki
Donating to the Museum
In New Leaf
Upon being donated, the Stinkbug can be found in the room of the bug exhibit with the light in, resting on a tree near the light.
"Stinkbugs are known for their foul smell, enough to drive away most predators and people. The smell is so strong that if they release it in an airtight place, they pass out from their own smell. They like to gather in clumps to stay warm in sunshine, though they will seek out warm houses as well."
Names in other languages