photoreceptor cell R1 & axon
photoreceptor cell R2 & axon
photoreceptor cell R3 & axon
photoreceptor cell R4 & axon
photoreceptor cell R5 & axon
photoreceptor cell R6 & axon
Mid third instar larvae show the majority of R cell axons fail to enter the optic stalk, they remain as a clump at the entrance to the stalk. In the developing optic ganglia the lamina precursor cells (LPC) are largely missing.