Third to sixth instar larvae of the aquatic firefly Luciola substriata swim with their ventral side up, including when they were searching for prey. When larvae were engaged in swimming, the thoracic legs sculled backwards continuously, while the abdomen could curve upward and downwards. The pygopodium located in the end of abdomen enable larvae to grasp and adhere on floating objects that also help start or cease swimming. When larvae in back-swimming changed direction, the larval abdomen curved clockwise or counterclockwise quickly and then unbent. The legs movement of larvae consists of eight different stroke patterns. The larvae averaged 1.6 strokes per sec and 0.6 wiggle of abdomen per sec. Larvae swim slowly with the speed of 0.9 m/h.