General appearance of Etiella hobsoni (Butler) and symptoms of soybean pods caused by its larvae were quite similar to those of Etiella zinckenella (Treitschke). Morphological characteristics to identify the two species were made clear for each developmental stage. E. hobsoni is distributed from Southeast Asia including Indonesia to Australia, while E. zinckenella is widely distributed throughout the tropical and temperate zones in the world. Some ecological differences, such as a development period, larval movement, intraspecific competition and host plants, were found between the two species. The population density of Etiella larvae is low in the wet season, but it increases in the dry season.