Image of Philopthalmus sp.; a. Drawing of cercaria structure b. Cercaria stained with 0.5% neutral red c. Redia stained with 0.5% neutral red d.–g. Images of Scanning Electronmicroscope Abbreviations: os – oral sucker, p – pharynx, ep – esophagus, vs – ventral sucker, in – intestine, eb – excretory bladder, ta – tail, ad – adhesive gland, re – redia, c – cercaria, b – body (scale a, b = 100 µm, c = 50 µm).