Genus Euroleon is belongs to family Myrmeleontidae and tribe Myrmeleontini, including, 9 genera and more than 200 species. The genus Euroleon was originally described by Esben-Petersen (1918) and the European species Myrmeleon europeaus Mclach, 1873 was moved to new genus as the type species, which is considered as a junior synonym of E. nostras now. Myrmeleon Linnaeus, 1767 is the nearest genus to Euroleon; Both are distinguished by wing spots and veins angle of Cua1 and Cua2. The vein angle of Euroleon is smaller than Myrmeleon and two veins of Euroleon almost parallel while in Myrmeleon is not parallel. Among Euroleon species, E. parvus Holzel, 1972 was introduced from Afghanestan (type locality). The species was then reported from Iran by Mirmoayedi et al. 1999. In this research we studied two species of genus Euroleon: E. parvus (2♀: Iran, Golestan Province, Golestan National Park, Almeh) and E. nostras (1♂: Iran, Golestan province, Kalaleh). in Hayk Mirzayans Insect Museum, Tehran, Iran. The species are rather similar, wings membrane are transparent, fore wings of two species with dark brown shadows. Two species could be recognized by the differences in wings shadow and pattern of pronotum. E. nostras with large brown shadow in cubital area to inner border of fore wing while E. parvus lacks it. Pronotum E. parvus has brown pattern with a yellow middle line and two yellow circles on both sides and two brown stripes up to half of each lateral edges of pronotum, about E. nostros is unicolor brown with yellow narrow line.