The muscid shoot-fly Atherigona reversura Villeneuve (Diptera: Muscidae), recently introduced to North America, is reported for the first time from the Neotropical Region: Mexico, Chiapas, Chiapa de Corzo. Information about distribution throughout the continent is summarized. Morphology of the second and third instar larva and puparium is described using light microscopy techniques, including photographs of posterior spiracles and cephaloskeleton as well as line drawings of the latter. Detailed scanning electron microscopy documentation is provided for the following morphological structures of the third instar larva: pseudocephalon; antennal complex; maxillary palpus; facial mask; ventral organ; thoracic and abdominal spinulation; bubble membrane; anal division; and anal plate. Previous descriptions of immature stages of Atherigona Rondani, particularly details of the cephaloskeleton, are revised.