Abstract: Marianna VÁLYI Nagy & Sándor CSŐSZ Marianna Vályi Nagy (contact author), Department of Entomology, Corvinus University of Budapest, 44 Ménesi u., H-1118 Budapest, Hungary. E-mail: valyi@citromail.hu Dr. Sándor Csősz, Department of Zoology, Hungarian Natural History Museum, 13 Baross u., H-1088 Budapest, Hungary. E-mail: csosz@zoo.zoo.nhmus.hu Myrmecol. News 10: 124 There are four endangered species of the genus Maculinea in Hungary. The Maculinea alcon (Denis & SCHIFFERMÜLLER, 1775) - M. rebeli (Hirschke, 1904) complex is indicated by the latest genetic research to consist of ecological races of one species, whereas some authors regard them as subspecies (Als & al. 2004, Bereczki & al. 2005). During the 20th century, most of the populations declined. Today Large Blue butterflies are highly endangered throughout the Carpathian Basin: All species are included in both, the Hungarian and the European red data lists. These butterflies display a particular parasitic lifestyle: The early instars consume flower buds of specific…