Abstract
Simulium (Simulium) serenum sp. nov. is described from reared female adult and pupal specimens collected from Hualien, Taiwan, and is placed in the griseifrons species-group within the subgenus Simulium. This new species is characterized by the cocoon with a deep cleft on the anterodorsal surface and a large window on each anterolateral surface, which separates it from all known species of this species group. This is the third species of the griseifrons species-group so far recorded from Taiwan.
