The A. delineata species-group Diagnosis. The male genitalia of the species-group are characterized by the following characters: (1) the valva is broadened medially and subapically and has a strongly concave costal margin; (2) the medial costal process has a narrow tip; (3) the distal costal process is massive and bears a few of various-sized and shaped trigonal or spine-like processes; the number, size and shape of the processes vary within the same species; (4) the sacculus is narrowed distally and weakly setose; (5) the distal saccular process is very short; (6) the aedeagus is long and narrow. The female genitalia of the species-group are characterized by the large postvaginal plate. Distribution. The species-group is distributed in mainland China and Taiwan Island.

Published as part of Volynkin, Anton V. & Wu, Shipher, 2020, A review of the subgenus Delineatia Volynkin & Huang, 2019 of the genus Ammatho Walker, 1855, with descriptions of two new species from Taiwan and Vietnam (Lepidoptera, Erebidae, Arctiinae, Lithosiini), pp. 237-250 in Zootaxa 4801 (2) on pages 238-239, DOI: 10.11646/zootaxa.4801.2.2, http://zenodo.org/record/3900426