Atlas of Czech Butterflies is a free offline application available on Android. It contains descriptions of all Czech butterflies using information from the website lepidoptera.cz, a website created by the Institute of Entomology, Biology Center under the Academy of Sciences in the Czech Republic. The app offers a butterfly gallery and quizzes, but it is only available in the Czech language.

The app is a useful tool for those interested in learning about day-flying butterflies in the Czech Republic. The descriptions are informative and based on reliable sources, making it a trustworthy guide. The butterfly gallery is visually appealing and offers high-quality images of the different species. The quizzes are a fun way to test your knowledge and learn more about these fascinating creatures. However, it is important to note that the app is only available in Czech, which may limit its accessibility to non-Czech speakers.