postabdomen

postabdomen (noun; Latin post, after; abdomen, belly): 1. (Arthropoda) The usually slender, modified posterior segment of the abdomen of Crustacea and Insecta.

2. (Arthropoda: Chelicerata) The anal tubercle in spiders; in scorpions the metasoma or posterior narrower five segments of the abdomen

See also: telson.