First record of the genus Eulocastra Butler, 1886 (Lepidoptera, Noctuidae) from the Indochina Peninsula, with notes on the distribution and host associations of Eulocastra sasakii Sugi, 1985

Eulocastra sasakii Sugi, 1985 (Lepidoptera, Noctuidae) was previously known only from Japan and has, therefore, been regarded as a Japanese endemic species. The species is considered threatened in Japan and is currently listed as Vulnerable (Category II) at the national level and in regional Red Data Books. Although both male and female specimens were included in the original description, only the male genitalia were described and illustrated, leaving the female genitalia unknown. Furthermore, Molinia japonica Hack., a temperate East Asian grass, has been reported as the only known host plant of the species. The genus Eulocastra Butler, 1886 and E. sasakii Sugi, 1985 are recorded from Cambodia and the Indochina Peninsula for the first time. Adults of both sexes, the wing venation and the male genitalia are illustrated and the female genitalia are described and illustrated for the first time. This record extends the known distribution of the species from Japan to Southeast Asia and raises the possibility of an alternative host plant association in Cambodia.