Flies have strong defects in the eye, antenna and maxillary palps. The facets are completely fused and the eye surface appears as a mass of tissue with strikingly reduced bristles. There is very little residual eye pigment. Recruitment of the photoreceptor clusters and progression of the morphogenetic furrow proceeds normally, although in late discs the number of axons in the optic stalk appears reduced and they appear damaged. Pupal eye discs contain significantly greater numbers of apoptotic cells compared to wild-type discs. Pupal eye discs contain significantly greater numbers of apoptotic cells compared to wild-type discs. There are gross changes in the arrangement of photoreceptors and the pigment layer is disorganised in the optic lobe. The morphology of the lamina appears normal. The basiconic sensilla of the antenna fail to develop, and the number of trichoid sensilla on the antenna is reduced. Females show a greater reduction in trichoid sensilla than males. The maxillary palps show a striking reduction in the numbers of normal basiconic-like sensilla. The socket and sensory neurons of these mutant sensilla appear normal.