Cover legend: An artistically stylized view of a mutant Drosophila visual system. When the transcription factor Runt is mis-expressed in the developing visual system, seen here at 40% pupal development, many photoreceptor axons (green) bypass the lamina and terminate in the medulla. The pupal brain was immunohistochemically labeled for the neuronal nuclei (anti-ELAV, magenta), photoreceptor axons (anti-Chaoptin, green) and glial nuclei (anti-Repo, blue). For more information, see the article by Edwards et al. in this issue (pages 828–841).