USFWS proposes to list the eastern regal fritillary (Argynnis idalia idalia) as an endangered species and to list the western regal fritillary (A. i. occidentalis) as a threatened species under the ESA. This determination also serves as their 12-month finding on a petition to list the regal fritillary, as these two subspecies make up the entire species. After a review of the best available scientific and commercial information, they find that listing both subspecies is warranted. Accordingly, they propose to list the eastern subspecies as endangered and the western subspecies as threatened with protective regulations issued under section 4(d) of the Act (a "4(d) rule"). They find that designation of critical habitat for both subspecies is not determinable at this time. They will accept comments received or postmarked on or before 7 October 2024. POC is listed in the Federal Register. (Federal Register 6 August 2024 [Proposed Rule] Pages 63888-63909)