Hox genes establish the anterior-posterior axis. The Hox gene Antennapedia is expressed in the thoracic region but has previously been reported to be dispensable for wing development. Now, Xiaoling Tong and colleagues find that Antennapedia is indeed required for wing development in the silkworm (Bombyx mori), in Drosophila and in Tribolium. The authors show that BmAntp is expressed at low levels in larvae, but expression increases through late larval and pupal stages. This expression profile correlates with their observation that wing discs from the main larval stage from BmAntp+/– mutants are comparable with wild type, whereas wing discs from larvae at later stages display dysplasia. Furthermore, BmAntp+/- adults have small wrinkled wings. To understand the mechanism by which Antennapedia regulates wing development, the authors use in vitro assays to show that BmAntp binds directly to the upstream regions of shade, which encodes an ecdysone pathway enzyme, and the cuticular protein-encoding gene CPH28, both of which are important for wing development. The researchers find that RNAi knockdown of Antennapedia in late larval and pupal development also results in defective wing development in both Tribolium and Drosophila. Together, these data indicate a conserved role for Antennapedia in wing development.