The collection of butterflies and chrysalis from Jan Patočka is the most extensive and scientifically valuable natural history collection in the Museum of Central Slovakia. In 2025, we commemorate the 100th anniversary of the birth of its collector, an ethnologist, doc. RNDr. Jan Patočka, DrSc. who devoted his life to research into butterflies that live on forest trees. He disagreed with the use of chemical sprays on forest undergrowth and for this reason, he developed biological methods of pest control and tree protection. When working, he would collect butterflies in their caterpillar and chrysalis states and studied how...