The alate processes (“wings”) of the notodelphyid copepod Notopterophoms papilio Hesse have been studied at light microscope and electron microscope (scanning and transmission) level. General cuticular structure and three integumental organs occurring on the wings are described. These latter comprise a glandular pore, a bulb-like protrusion and a long, hair-like seta. It is suggested that all three may be concerned with maximising naupliar release and safe extrusion of young from the potentially hazardous confines of the ascidian host's pharynx. The proposed mechanism involves rheoreception and the detection of small changes in hydrostatic pressure through the medium of electrode action in the cuticle.