Entomological collections include over 20,000,000 specimens, representing over 5,400 species, mainly from eastern Poland. They are stored dry, in the form of permanent microscopic sliders, or preserved in alcohol. Many of them still require detailed study. They are of great scientific value, both in Poland and Europe. This is evidenced by the presence of 21 specimens of descriptive types, including 11 holotypes and 10 paratypes. The collection includes approximately 10,000 specimens of beetles, bugs and butterflies caught mainly in the second half of the last century in Bulgaria, Romania, the southern and western parts of present-day Ukraine, as well as in the former Soviet republics, mainly in Kazakhstan, Azerbaijan, Tajikistan, Turkmenistan, Uzbekistan, Georgia, as well as in Iran.