The species Ambrysus sonorensis Usinger, 1946 was originally described based on only the male holotype from northwestern Mexico; nonetheless, features of the females are the most reliable to correctly identify a species in the genus Ambrysus Stål. Accordingly, this study provides the description of the hitherto unknown female of A. sonorensis, including the morphological features to properly establish its identity. Additionally, important features of the male not reported in the original description, some of which validate the inclusion of the species in the A. signoreti Stål complex, are herein described and illustrated for the first time. Also, new distribution records are provided and the species range is discussed.