High Quality Content by WIKIPEDIA articles! Osmoderma eremita, the hermit beetle or Russian leather beetle, is a species of European beetle in the family Scarabaeidae. The larvae develop in hollow trees. Oak is the most important tree species, but the larvae may develop in any tree species with suitable hollows. Due to habitat loss and fragmentation, the species has decreased all over its distribution range. For that reason the species is protected in most European countries, and has been given the highest priority according to the EU`s Habitats Directive.