Promachus yesonicus, or in Japanese, is a species of robber flies. In Japanese, "shioya" means a salt merchant (someone who makes or deals in salt), and "abu" means a horse-fly. This insect is called "shioya-abu" because the males have a white tip to their tail that resembles salt. Distribution Promachus yesonicus is found throughout Japan from Hokkaido to Okinawa. They are visible from June to September. Description Male Promachus yesonicus have a white cotton-like bud at the end of their tails, while females do not. Adults can reach in length. References Asilidae Insects described in 1887 Articles containing video clips Insects of Japan