The Entomological Museum in León has an interesting and colorful collection of insect species. The establishment has three permanent exhibitions: scarabs, diurnal butterflies, and nocturnal butterflies.
In addition, the museum also frequently exhibits species from the different natural reserves throughout Nicaragua. These species are sent to the museum for investigation by universities and other investigators. There is also a collection of rocks and shells from different parts of the world.
If the door is closed, knock the door or ring the bell and someone will open it for you. This might also work outside opening hours. It is very rare there is no one around during opening hours, but if you want to be sure, call the museum beforehand. This will also allow them to make the exhibition room - which is also used to work on the collection - visitor-ready.
More information about the museum can be found at their website.
The museum's address is: 2 blocks south of the San Juan church.