A survey on the occurrence of caddisflies, distribution, and abundance was carried out in four protected areas of Khlong Saeng Wildlife Sanctuary, and Khlong Phanom, Kaengkrung, Khao Sok National Parks in Surat Thani Province, southern Thailand. These are areas found in the west of Surat Thani province that hold the Lower Phuket mountains, an off-shoot range linked to the great Tenasserim Hills called the Indo-Malayan Mountain system. The streams of Khlong Phanom, Khlong Yan, Khlong Sok, and Khlong Saeng tributaries of the Phum Duang River were used for this investigation. The largest water source of River Tapi is Phum Duang, which drains the wetlands of the Tapi River. This study was conducted in March-December 2019. samples were collected once in the dry season and twice during the rainy season, giving a sum of three collections during the research. The results revealed that two hundred and one (201) species were caught and identified, this falls into fifty-one (51) genera, and eighteen (18) families. Families Ecnomidae, Philopotamidae, Hydropsychidae, and Leptoceridae are extensive and constitute about sixty percent (60%) of the insects sampled. Cheumatopsyche contexta ULMER 1951* , Cheumatopsyche opposita BANKS 1931* , and Polymorphanisus scutellatus BANKS 1939* , were the new records observed. Water quality variables were correlated to some species, and the analysis revealed that some species demonstrated negative and positive responses to various water parameters.

Keywords : National Parks, Occurrence, Tributaries, New Records.