Animal Crossing: New Horizons/International Museum Day

The International Museum Day is an event held from May 18 to May 31. The fish, bug and fossil galleries in the Museum will each have tree stamp stations. To get a stamp, find the station and interact with it. It will tell you a summary about the section you are in and then you're free to stamp your card.

Bug gallery
The fist two stations are in the first room. Go up to find the first stamp, Shady Path. Continue across the bridge to the left to find the Coconut Corner stamp station. The last station is in front of the lab - the shortest way is to go back across the bridge and up to the next room. Go up the stairs to acquire the The Lab stamp.

Talk to Blathers after obtaining all the stamps to acquire the completition stamp and the prize, Bug Plaque.