(Gerris lacustris)
Water striders vary in length ranging between 8 millimetres (0.31 in) and 10 mm (0.39 in) in size.Their body shape is very slender and elongated.They have six legs;the first pair is short and stubby while the other two pairs are thin and elongated which are used for moving over the water surface which we call "walking on water".The first pair of legs is used for holding its prey,the middle pair propels the bug along the surface of the water with either a rowing or jumping motion,and the hind pair of legs is used as rudders.The entire body of G.lacustris including its legs is covered with many tiny hairs that have a wax-like coating.G.lacustris are dark brown in colour.Water striders have very strong sucking mouthparts known as a rostrum or beak.