In Thailand, long-legged flies have been published at least five papers but there is only study about genus Phacaspis so far. In 2001, Patrick Grootaert and Henk Meuffels described new species Phacaspis mitis in Thailand. They were found in Krabi province, Trang province and Satun province. In 1996 Phacaspis petiolata was reported in Prachuap Khiri Khan province by Patrick Grootaert. However, previous study of phacaspis focused on taxonomy but there is no study in terms of molecular genetics in Thailand.